<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 5.6a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: http://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Source; Value: gnbt.xfr; Date: 2020%2D12%2D21T15:41:14Z -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x80080000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef roleURI="http://generex.com/role/DocumentAndEntityInformation" xlink:href="gnbt-20201031.xsd#DocumentAndEntityInformation" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/UnauditedCondensedInterimConsolidatedBalanceSheets" xlink:href="gnbt-20201031.xsd#UnauditedCondensedInterimConsolidatedBalanceSheets" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/UnauditedCondensedInterimConsolidatedBalanceSheetsParenthetical" xlink:href="gnbt-20201031.xsd#UnauditedCondensedInterimConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfOperationsAndComprehensiveLoss" xlink:href="gnbt-20201031.xsd#UnauditedCondensedInterimConsolidatedStatementsOfOperationsAndComprehensiveLoss" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfChangesInStockholdersEquity" xlink:href="gnbt-20201031.xsd#UnauditedCondensedInterimConsolidatedStatementsOfChangesInStockholdersEquity" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfCashFlows" xlink:href="gnbt-20201031.xsd#UnauditedCondensedInterimConsolidatedStatementsOfCashFlows" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfCashFlowsParenthetical" xlink:href="gnbt-20201031.xsd#UnauditedCondensedInterimConsolidatedStatementsOfCashFlowsParenthetical" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/OrganizationAndBusiness" xlink:href="gnbt-20201031.xsd#OrganizationAndBusiness" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="gnbt-20201031.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/CommitmentsAndContingencies" xlink:href="gnbt-20201031.xsd#CommitmentsAndContingencies" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Inventory" xlink:href="gnbt-20201031.xsd#Inventory" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/PropertyAndEquipment" xlink:href="gnbt-20201031.xsd#PropertyAndEquipment" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/GoodwillAndIntangibleAssets" xlink:href="gnbt-20201031.xsd#GoodwillAndIntangibleAssets" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NotesPayable" xlink:href="gnbt-20201031.xsd#NotesPayable" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/DerivativeLiability" xlink:href="gnbt-20201031.xsd#DerivativeLiability" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/StockholdersEquity" xlink:href="gnbt-20201031.xsd#StockholdersEquity" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/RedeemableNon-controllingInterest" xlink:href="gnbt-20201031.xsd#RedeemableNon-controllingInterest" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Stock-basedCompensation" xlink:href="gnbt-20201031.xsd#Stock-basedCompensation" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Warrants" xlink:href="gnbt-20201031.xsd#Warrants" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NetIncomePerShareEps" xlink:href="gnbt-20201031.xsd#NetIncomePerShareEps" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/IncomeTaxes" xlink:href="gnbt-20201031.xsd#IncomeTaxes" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/SubsequentEvents" xlink:href="gnbt-20201031.xsd#SubsequentEvents" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="gnbt-20201031.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:href="gnbt-20201031.xsd#SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/InventoryTables" xlink:href="gnbt-20201031.xsd#InventoryTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/PropertyAndEquipmentTables" xlink:href="gnbt-20201031.xsd#PropertyAndEquipmentTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/GoodwillAndIntangibleAssetsTables" xlink:href="gnbt-20201031.xsd#GoodwillAndIntangibleAssetsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NotesPayableTables" xlink:href="gnbt-20201031.xsd#NotesPayableTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/DerivativeLiabilityTables" xlink:href="gnbt-20201031.xsd#DerivativeLiabilityTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/StockholdersEquityTables" xlink:href="gnbt-20201031.xsd#StockholdersEquityTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Stock-basedCompensationTables" xlink:href="gnbt-20201031.xsd#Stock-basedCompensationTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/WarrantsTables" xlink:href="gnbt-20201031.xsd#WarrantsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NetIncomePerShareEpsTables" xlink:href="gnbt-20201031.xsd#NetIncomePerShareEpsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/OrganizationOfBusinessAndGoingConcernDetailsNarrative" xlink:href="gnbt-20201031.xsd#OrganizationOfBusinessAndGoingConcernDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:href="gnbt-20201031.xsd#SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:href="gnbt-20201031.xsd#CommitmentsAndContingenciesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/InventoryDetails" xlink:href="gnbt-20201031.xsd#InventoryDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/PropertyAndEquipmentDetails" xlink:href="gnbt-20201031.xsd#PropertyAndEquipmentDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/PropertyAndEquipmentDetailsNarrative" xlink:href="gnbt-20201031.xsd#PropertyAndEquipmentDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/GoodwillAndIntangibleAssetsIntangibleAssetsDetails" xlink:href="gnbt-20201031.xsd#GoodwillAndIntangibleAssetsIntangibleAssetsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/GoodwillAndIntangibleAssetsEstimatedAmortizationExpenseDetails" xlink:href="gnbt-20201031.xsd#GoodwillAndIntangibleAssetsEstimatedAmortizationExpenseDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/GoodwillAndIntangibleAssetsDetailsNarrative" xlink:href="gnbt-20201031.xsd#GoodwillAndIntangibleAssetsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NotesPayableDetails" xlink:href="gnbt-20201031.xsd#NotesPayableDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NotesPayableDetails1" xlink:href="gnbt-20201031.xsd#NotesPayableDetails1" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NotesPayableDetailsNarrative" xlink:href="gnbt-20201031.xsd#NotesPayableDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/DerivativeLiabilityDetails" xlink:href="gnbt-20201031.xsd#DerivativeLiabilityDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/StockholdersEquityDetails" xlink:href="gnbt-20201031.xsd#StockholdersEquityDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/StockholdersEquityDetailsNarrative" xlink:href="gnbt-20201031.xsd#StockholdersEquityDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/RedeemableNon-controllingInterestDetailsNarrative" xlink:href="gnbt-20201031.xsd#RedeemableNon-controllingInterestDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Stock-basedCompensation-CommonStockOptionsGrantedForfeitedOrExpiredAndExercisedDetails" xlink:href="gnbt-20201031.xsd#Stock-basedCompensation-CommonStockOptionsGrantedForfeitedOrExpiredAndExercisedDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Stock-basedCompensation-Non-vestedOptionsGrantedForfeitedOrExpiredAndExercisedDetails" xlink:href="gnbt-20201031.xsd#Stock-basedCompensation-Non-vestedOptionsGrantedForfeitedOrExpiredAndExercisedDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Stock-basedCompensation-FairValueAssumptionsUsedInBlack-scholesOption-pricingDetails" xlink:href="gnbt-20201031.xsd#Stock-basedCompensation-FairValueAssumptionsUsedInBlack-scholesOption-pricingDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/Stock-basedCompensationDetailsNarrative" xlink:href="gnbt-20201031.xsd#Stock-basedCompensationDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/WarrantsDetails" xlink:href="gnbt-20201031.xsd#WarrantsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/WarrantsDetails1" xlink:href="gnbt-20201031.xsd#WarrantsDetails1" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/WarrantsDetailsNarrative" xlink:href="gnbt-20201031.xsd#WarrantsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/NetIncomePerShareEps-ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareDetails" xlink:href="gnbt-20201031.xsd#NetIncomePerShareEps-ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/IncomeTaxesDetailsNarrative" xlink:href="gnbt-20201031.xsd#IncomeTaxesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://generex.com/role/SubsequentEventsDetailsNarrative" xlink:href="gnbt-20201031.xsd#SubsequentEventsDetailsNarrative" xlink:type="simple" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/DocumentAndEntityInformation" xlink:title="00000001 - Document - Document and Entity Information" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/UnauditedCondensedInterimConsolidatedBalanceSheets" xlink:title="00000002 - Statement - UNAUDITED CONDENSED INTERIM CONSOLIDATED BALANCE SHEETS">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesACumulativeRedeemablePerpetualPreferredStockMember" xlink:label="loc_GNBTSeriesACumulativeRedeemablePerpetualPreferredStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_GNBTSeriesACumulativeRedeemablePerpetualPreferredStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaapAssetsAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAssetsAbstract_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaapAssetsCurrentAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapAssetsCurrentAbstract_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaapCashAndCashEquivalentsAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapCashAndCashEquivalentsAtCarryingValue_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaapAccountsReceivableNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapAccountsReceivableNet_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaapInventoryNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapInventoryNet_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaapOtherAssetsCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsCurrentAbstract_50" xlink:to="loc_us-gaapOtherAssetsCurrent_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaapAssetsCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapAssetsCurrent_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapPropertyPlantAndEquipmentNet_50" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaapGoodwill_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapGoodwill_50" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsNet_50" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaapOperatingLeaseRightOfUseAsset_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapOperatingLeaseRightOfUseAsset_50" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaapOtherAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAssetsAbstract_50" xlink:to="loc_us-gaapOtherAssets_50" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaapAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAssets_50" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaapLiabilitiesCurrentAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrent_50" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NotesPayable" xlink:label="loc_us-gaapNotesPayable_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapNotesPayable_50" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PayableToFoundationForServices" xlink:label="loc_GNBTPayableToFoundationForServices_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_GNBTPayableToFoundationForServices_50" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InterestPayableToFoundation" xlink:label="loc_GNBTInterestPayableToFoundation_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_GNBTInterestPayableToFoundation_50" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:label="loc_us-gaapDueToRelatedPartiesCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapDueToRelatedPartiesCurrent_50" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapOperatingLeaseLiabilityCurrent_50" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_RefundableAdvances" xlink:label="loc_GNBTRefundableAdvances_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_GNBTRefundableAdvances_50" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaapDeferredIncomeTaxLiabilitiesNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesCurrentAbstract_50" xlink:to="loc_us-gaapDeferredIncomeTaxLiabilitiesNet_50" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaapLiabilitiesCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLiabilitiesCurrent_50" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermNotesPayable" xlink:label="loc_us-gaapLongTermNotesPayable_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapLongTermNotesPayable_50" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:label="loc_us-gaapDerivativeLiabilitiesNoncurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_us-gaapDerivativeLiabilitiesNoncurrent_50" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_CommonStockPayableNoncurrent" xlink:label="loc_GNBTCommonStockPayableNoncurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquityAbstract_50" xlink:to="loc_GNBTCommonStockPayableNoncurrent_50" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaapLiabilities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLiabilities_50" xlink:type="arc" order="27" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount" xlink:label="loc_us-gaapRedeemableNoncontrollingInterestEquityCarryingAmount_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRedeemableNoncontrollingInterestEquityCarryingAmount_50" xlink:type="arc" order="28" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaapStockholdersEquityAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquityAbstract_50" xlink:type="arc" order="29" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaapCommonStockValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapCommonStockValue_50" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaapPreferredStockValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapPreferredStockValue_50" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="loc_us-gaapAdditionalPaidInCapitalCommonStock_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapAdditionalPaidInCapitalCommonStock_50" xlink:type="arc" order="32" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit_50" xlink:type="arc" order="33" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax_50" xlink:type="arc" order="34" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaapMinorityInterest_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStockholdersEquityAbstract_50" xlink:to="loc_us-gaapMinorityInterest_50" xlink:type="arc" order="35" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquity_50" xlink:type="arc" order="36" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquity_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLiabilitiesAndStockholdersEquity_50" xlink:type="arc" order="37" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/UnauditedCondensedInterimConsolidatedBalanceSheetsParenthetical" xlink:title="00000003 - Statement - UNAUDITED CONDENSED INTERIM CONSOLIDATED BALANCE SHEETS (Parenthetical)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesACumulativeRedeemablePerpetualPreferredStockMember" xlink:label="loc_GNBTSeriesACumulativeRedeemablePerpetualPreferredStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_GNBTSeriesACumulativeRedeemablePerpetualPreferredStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaapCommonStockSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesIssued_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaapPreferredStockParOrStatedValuePerShare_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockParOrStatedValuePerShare_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaapPreferredStockSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesIssued_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding_50" xlink:type="arc" order="7" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfOperationsAndComprehensiveLoss" xlink:title="00000004 - Statement - UNAUDITED CONDENSED INTERIM CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfChangesInStockholdersEquity" xlink:title="00000005 - Statement - UNAUDITED CONDENSED INTERIM CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS&apos; EQUITY (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaapPreferredStockMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapPreferredStockMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaapAdditionalPaidInCapitalMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAdditionalPaidInCapitalMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaapRetainedEarningsMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapRetainedEarningsMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaapAccumulatedOtherComprehensiveIncomeMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAccumulatedOtherComprehensiveIncomeMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SubTotalMember" xlink:label="loc_GNBTSubTotalMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_GNBTSubTotalMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaapNoncontrollingInterestMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapNoncontrollingInterestMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaapSharesOutstanding_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesOutstanding_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquity_90" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_90" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueShareBasedCompensation_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueShareBasedCompensation_90" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_90" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_90" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_IssuanceOfCommonStockPayableShares" xlink:label="loc_GNBTIssuanceOfCommonStockPayableShares_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTIssuanceOfCommonStockPayableShares_90" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_IssuanceOfCommonStockPayableValue" xlink:label="loc_GNBTIssuanceOfCommonStockPayableValue_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTIssuanceOfCommonStockPayableValue_90" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ConversionOfDebtToEquityShares" xlink:label="loc_GNBTConversionOfDebtToEquityShares_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTConversionOfDebtToEquityShares_90" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ConversionOfDebtToEquityValue" xlink:label="loc_GNBTConversionOfDebtToEquityValue_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTConversionOfDebtToEquityValue_90" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_90" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueAcquisitions_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueAcquisitions_90" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ReductionOfDerivativesLiabilities" xlink:label="loc_GNBTReductionOfDerivativesLiabilities_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTReductionOfDerivativesLiabilities_90" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_IssuanceOfCommonStockAndWarrantsWithAttributedDerivativeLiabilityFromPipeOfferingShares" xlink:label="loc_GNBTIssuanceOfCommonStockAndWarrantsWithAttributedDerivativeLiabilityFromPipeOfferingShares_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTIssuanceOfCommonStockAndWarrantsWithAttributedDerivativeLiabilityFromPipeOfferingShares_90" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_IssuanceOfCommonStockAndWarrantsWithAttributedDerivativeLiabilityFromPipeOfferingValue" xlink:label="loc_GNBTIssuanceOfCommonStockAndWarrantsWithAttributedDerivativeLiabilityFromPipeOfferingValue_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTIssuanceOfCommonStockAndWarrantsWithAttributedDerivativeLiabilityFromPipeOfferingValue_90" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DeemedDividendRelatedToIssuanceOfWarrantsContainingDerivativeLiabilities" xlink:label="loc_GNBTDeemedDividendRelatedToIssuanceOfWarrantsContainingDerivativeLiabilities_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTDeemedDividendRelatedToIssuanceOfWarrantsContainingDerivativeLiabilities_90" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SettlementOfDerivativeLiabilityFromExerciseOfWarrants" xlink:label="loc_GNBTSettlementOfDerivativeLiabilityFromExerciseOfWarrants_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTSettlementOfDerivativeLiabilityFromExerciseOfWarrants_90" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SaleOfCommonStockShares" xlink:label="loc_GNBTSaleOfCommonStockShares_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTSaleOfCommonStockShares_90" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SaleOfCommonStockValue" xlink:label="loc_GNBTSaleOfCommonStockValue_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTSaleOfCommonStockValue_90" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ExerciseOfSeriesDWarrantsShares" xlink:label="loc_GNBTExerciseOfSeriesDWarrantsShares_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTExerciseOfSeriesDWarrantsShares_90" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ExerciseOfSeriesDWarrantsValue" xlink:label="loc_GNBTExerciseOfSeriesDWarrantsValue_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTExerciseOfSeriesDWarrantsValue_90" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="loc_us-gaapStockRepurchasedDuringPeriodShares_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockRepurchasedDuringPeriodShares_90" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="loc_us-gaapStockRepurchasedDuringPeriodValue_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockRepurchasedDuringPeriodValue_90" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PurchaseOfSharesInSubsidiary" xlink:label="loc_GNBTPurchaseOfSharesInSubsidiary_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPurchaseOfSharesInSubsidiary_90" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_IssuanceOfStockOptions" xlink:label="loc_GNBTIssuanceOfStockOptions_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTIssuanceOfStockOptions_90" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TemporaryEquityForeignCurrencyTranslationAdjustments" xlink:label="loc_us-gaapTemporaryEquityForeignCurrencyTranslationAdjustments_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapTemporaryEquityForeignCurrencyTranslationAdjustments_90" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLoss_90" xlink:type="arc" order="27" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfCashFlows" xlink:title="00000006 - Statement - UNAUDITED CONDENSED INTERIM CONSOLIDATED STATEMENTS OF CASH FLOWS" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/UnauditedCondensedInterimConsolidatedStatementsOfCashFlowsParenthetical" xlink:title="00000007 - Statement - UNAUDITED CONDENSED INTERIM CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/OrganizationAndBusiness" xlink:title="00000008 - Disclosure - Organization of Business and Going Concern" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="00000009 - Disclosure - Summary of Significant Accounting Policies" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/CommitmentsAndContingencies" xlink:title="00000010 - Disclosure - Commitments and Contingencies" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Inventory" xlink:title="00000011 - Disclosure - Inventory" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/PropertyAndEquipment" xlink:title="00000012 - Disclosure - Property and Equipment" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/GoodwillAndIntangibleAssets" xlink:title="00000013 - Disclosure - Goodwill and Intangible Assets" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NotesPayable" xlink:title="00000014 - Disclosure - Notes Payable" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/DerivativeLiability" xlink:title="00000015 - Disclosure - Derivative Liability" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/StockholdersEquity" xlink:title="00000016 - Disclosure - Stockholders&apos; Equity" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/RedeemableNon-controllingInterest" xlink:title="00000017 - Disclosure - Redeemable Non-Controlling Interest" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Stock-basedCompensation" xlink:title="00000018 - Disclosure - Stock-Based Compensation" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Warrants" xlink:title="00000019 - Disclosure - Warrants" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NetIncomePerShareEps" xlink:title="00000020 - Disclosure - Net Income Per Share (EPS)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/IncomeTaxes" xlink:title="00000021 - Disclosure - Income Taxes" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/SubsequentEvents" xlink:title="00000022 - Disclosure - Subsequent Events" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="00000023 - Disclosure - Summary of Significant Accounting Policies (Policies)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:title="00000024 - Disclosure - Summary of Significant Accounting Policies (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/InventoryTables" xlink:title="00000025 - Disclosure - Inventory (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/PropertyAndEquipmentTables" xlink:title="00000026 - Disclosure - Property and Equipment (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/GoodwillAndIntangibleAssetsTables" xlink:title="00000027 - Disclosure - Goodwill and Intangible Assets (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NotesPayableTables" xlink:title="00000028 - Disclosure - Notes Payable (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/DerivativeLiabilityTables" xlink:title="00000029 - Disclosure - Derivative Liability (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/StockholdersEquityTables" xlink:title="00000030 - Disclosure - Stockholders&apos; Equity (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Stock-basedCompensationTables" xlink:title="00000031 - Disclosure - Stock-Based Compensation (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/WarrantsTables" xlink:title="00000032 - Disclosure - Warrants (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NetIncomePerShareEpsTables" xlink:title="00000033 - Disclosure - Net Income Per Share (EPS) (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/OrganizationOfBusinessAndGoingConcernDetailsNarrative" xlink:title="00000034 - Disclosure - Organization of Business and Going Concern (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_WWDTMember" xlink:label="loc_GNBTWWDTMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTWWDTMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_MedisourceAndPantheonMember" xlink:label="loc_GNBTMedisourceAndPantheonMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_GNBTMedisourceAndPantheonMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_WorkingCapitalDeficiency" xlink:label="loc_GNBTWorkingCapitalDeficiency_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTWorkingCapitalDeficiency_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SecuredPromissoryNoteDescription" xlink:label="loc_GNBTSecuredPromissoryNoteDescription_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTSecuredPromissoryNoteDescription_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromRelatedPartyDebt" xlink:label="loc_us-gaapProceedsFromRelatedPartyDebt_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromRelatedPartyDebt_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRevenues_50" xlink:type="arc" order="4" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:title="00000035 - Disclosure - Summary of Significant Accounting Policies (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srtProductOrServiceAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtProductOrServiceAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaapProductMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_us-gaapProductMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ManagementServicesMember" xlink:label="loc_GNBTManagementServicesMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_GNBTManagementServicesMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RecognitionOfDeferredRevenue" xlink:label="loc_us-gaapRecognitionOfDeferredRevenue_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapRecognitionOfDeferredRevenue_70" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:title="00000036 - Disclosure - Commitments and Contingencies (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LitigationCaseAxis" xlink:label="loc_srtLitigationCaseAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtLitigationCaseAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LitigationCaseTypeDomain" xlink:label="loc_srtLitigationCaseTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtLitigationCaseAxis" xlink:to="loc_srtLitigationCaseTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LitigationCaseTypeDomain" xlink:label="loc_srtLitigationCaseTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtLitigationCaseAxis" xlink:to="loc_srtLitigationCaseTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DamagesForUnpaidInvoicesMember" xlink:label="loc_GNBTDamagesForUnpaidInvoicesMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtLitigationCaseTypeDomain" xlink:to="loc_GNBTDamagesForUnpaidInvoicesMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_BreachOfContractMember" xlink:label="loc_GNBTBreachOfContractMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtLitigationCaseTypeDomain" xlink:to="loc_GNBTBreachOfContractMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AlternativeExecutionGroupMember" xlink:label="loc_GNBTAlternativeExecutionGroupMember_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTAlternativeExecutionGroupMember_90" xlink:type="arc" order="91" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OlaregenMember" xlink:label="loc_GNBTOlaregenMember_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTOlaregenMember_220" xlink:type="arc" order="221" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_RegentysMember" xlink:label="loc_GNBTRegentysMember_230" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTRegentysMember_230" xlink:type="arc" order="231" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NSABPMember" xlink:label="loc_GNBTNSABPMember_240" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTNSABPMember_240" xlink:type="arc" order="242" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_deiLegalEntityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_deiLegalEntityAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_deiLegalEntityAxis" xlink:to="loc_deiEntityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_KSKZManagementMember" xlink:label="loc_GNBTKSKZManagementMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_GNBTKSKZManagementMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DiscoverGrowthFundMember" xlink:label="loc_GNBTDiscoverGrowthFundMember_160" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_GNBTDiscoverGrowthFundMember_160" xlink:type="arc" order="161" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_IliadMember" xlink:label="loc_GNBTIliadMember_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_GNBTIliadMember_180" xlink:type="arc" order="181" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ALTuCELLMember" xlink:label="loc_GNBTALTuCELLMember_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_GNBTALTuCELLMember_200" xlink:type="arc" order="201" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NDSMember" xlink:label="loc_GNBTNDSMember_300" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_GNBTNDSMember_300" xlink:type="arc" order="301" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OlaregenMember" xlink:label="loc_GNBTOlaregenMember_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTOlaregenMember_190" xlink:type="arc" order="191" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ClinicalTrialAgreementMember" xlink:label="loc_GNBTClinicalTrialAgreementMember_240" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_GNBTClinicalTrialAgreementMember_240" xlink:type="arc" order="241" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_COVID19CollaborationAgreementMember" xlink:label="loc_GNBTCOVID19CollaborationAgreementMember_270" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_GNBTCOVID19CollaborationAgreementMember_270" xlink:type="arc" order="271" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TransactionTypeAxis" xlink:label="loc_us-gaapTransactionTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTransactionTypeAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TransactionDomain" xlink:label="loc_us-gaapTransactionDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTransactionTypeAxis" xlink:to="loc_us-gaapTransactionDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TransactionDomain" xlink:label="loc_us-gaapTransactionDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTransactionTypeAxis" xlink:to="loc_us-gaapTransactionDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PreCommercializationStageMember" xlink:label="loc_GNBTPreCommercializationStageMember_270" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapTransactionDomain" xlink:to="loc_GNBTPreCommercializationStageMember_270" xlink:type="arc" order="272" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_CommercializationStageMember" xlink:label="loc_GNBTCommercializationStageMember_280" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapTransactionDomain" xlink:to="loc_GNBTCommercializationStageMember_280" xlink:type="arc" order="282" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ValueOfDamagesSought" xlink:label="loc_GNBTValueOfDamagesSought_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTValueOfDamagesSought_320" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainContingencyUnrecordedAmount" xlink:label="loc_us-gaapGainContingencyUnrecordedAmount_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapGainContingencyUnrecordedAmount_320" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyLawsuitFilingDate" xlink:label="loc_us-gaapLossContingencyLawsuitFilingDate_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLossContingencyLawsuitFilingDate_320" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNameOfPlaintiff" xlink:label="loc_us-gaapLossContingencyNameOfPlaintiff_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLossContingencyNameOfPlaintiff_320" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossRelatedToLitigationSettlement" xlink:label="loc_us-gaapGainLossRelatedToLitigationSettlement_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapGainLossRelatedToLitigationSettlement_320" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InterestPerAnnumFailureToPaySettlement" xlink:label="loc_GNBTInterestPerAnnumFailureToPaySettlement_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTInterestPerAnnumFailureToPaySettlement_320" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LitigationSettlementInterest" xlink:label="loc_us-gaapLitigationSettlementInterest_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLitigationSettlementInterest_320" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherCommitmentsDescription" xlink:label="loc_us-gaapOtherCommitmentsDescription_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOtherCommitmentsDescription_320" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LitigationSettlementAmountAwardedToOtherParty" xlink:label="loc_us-gaapLitigationSettlementAmountAwardedToOtherParty_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLitigationSettlementAmountAwardedToOtherParty_320" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_LitigationAwardsExercisableShares" xlink:label="loc_GNBTLitigationAwardsExercisableShares_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTLitigationAwardsExercisableShares_320" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ExercisePrice" xlink:label="loc_GNBTExercisePrice_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTExercisePrice_320" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_MemorandumOfUnderstandingDescription" xlink:label="loc_GNBTMemorandumOfUnderstandingDescription_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTMemorandumOfUnderstandingDescription_320" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaapDebtInstrumentCarryingAmount_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentCarryingAmount_320" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaapDebtInstrumentFaceAmount_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentFaceAmount_320" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="loc_us-gaapDebtInstrumentUnamortizedDiscount_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentUnamortizedDiscount_320" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IndefinitelivedIntangibleAssetsAcquired" xlink:label="loc_us-gaapIndefinitelivedIntangibleAssetsAcquired_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIndefinitelivedIntangibleAssetsAcquired_320" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AccruedLiquidatedDamages" xlink:label="loc_GNBTAccruedLiquidatedDamages_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTAccruedLiquidatedDamages_320" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MalpracticeLossContingencyAccrualUndiscounted" xlink:label="loc_us-gaapMalpracticeLossContingencyAccrualUndiscounted_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapMalpracticeLossContingencyAccrualUndiscounted_320" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ConsultingFees" xlink:label="loc_GNBTConsultingFees_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTConsultingFees_320" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyDamagesPaidValue" xlink:label="loc_us-gaapLossContingencyDamagesPaidValue_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLossContingencyDamagesPaidValue_320" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_CommonStockDescription" xlink:label="loc_GNBTCommonStockDescription_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTCommonStockDescription_320" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AdvancedToRelatedParty" xlink:label="loc_GNBTAdvancedToRelatedParty_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTAdvancedToRelatedParty_320" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_StockPurchaseAgreementDescription" xlink:label="loc_GNBTStockPurchaseAgreementDescription_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTStockPurchaseAgreementDescription_320" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LegalFees" xlink:label="loc_us-gaapLegalFees_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapLegalFees_320" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaapResearchAndDevelopmentExpense_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapResearchAndDevelopmentExpense_320" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PayableToFoundationForServices" xlink:label="loc_GNBTPayableToFoundationForServices_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPayableToFoundationForServices_320" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InterestPayableToFoundation" xlink:label="loc_GNBTInterestPayableToFoundation_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTInterestPayableToFoundation_320" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InterestAccruedPayableToFoundation" xlink:label="loc_GNBTInterestAccruedPayableToFoundation_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTInterestAccruedPayableToFoundation_320" xlink:type="arc" order="27" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ArbitrationFees" xlink:label="loc_GNBTArbitrationFees_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTArbitrationFees_320" xlink:type="arc" order="28" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ArbitrationExpenses" xlink:label="loc_GNBTArbitrationExpenses_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTArbitrationExpenses_320" xlink:type="arc" order="29" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SharesIssuedForLitigationSettlement" xlink:label="loc_GNBTSharesIssuedForLitigationSettlement_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTSharesIssuedForLitigationSettlement_320" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromOtherDebt" xlink:label="loc_us-gaapProceedsFromOtherDebt_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromOtherDebt_320" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccruedBonusesCurrent" xlink:label="loc_us-gaapAccruedBonusesCurrent_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAccruedBonusesCurrent_320" xlink:type="arc" order="32" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PrejudgmentInterest" xlink:label="loc_GNBTPrejudgmentInterest_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPrejudgmentInterest_320" xlink:type="arc" order="33" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_BonusCompensationDescription" xlink:label="loc_GNBTBonusCompensationDescription_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTBonusCompensationDescription_320" xlink:type="arc" order="34" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AccruedClaim" xlink:label="loc_GNBTAccruedClaim_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTAccruedClaim_320" xlink:type="arc" order="35" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/InventoryDetails" xlink:title="00000037 - Disclosure - Inventory (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/PropertyAndEquipmentDetails" xlink:title="00000038 - Disclosure - Property and Equipment (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:to="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaapPropertyPlantAndEquipmentTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:to="loc_us-gaapPropertyPlantAndEquipmentTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ComputersAndTechnologicalAssetsMember" xlink:label="loc_GNBTComputersAndTechnologicalAssetsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_GNBTComputersAndTechnologicalAssetsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="loc_us-gaapMachineryAndEquipmentMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapMachineryAndEquipmentMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaapFurnitureAndFixturesMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapFurnitureAndFixturesMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaapLeaseholdImprovementsMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapLeaseholdImprovementsMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaapPropertyPlantAndEquipmentGross_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPropertyPlantAndEquipmentGross_110" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaapAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_110" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPropertyPlantAndEquipmentNet_110" xlink:type="arc" order="2" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/PropertyAndEquipmentDetailsNarrative" xlink:title="00000039 - Disclosure - Property and Equipment (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/GoodwillAndIntangibleAssetsIntangibleAssetsDetails" xlink:title="00000040 - Disclosure - Goodwill and Intangible Assets: Intangible assets (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:label="loc_us-gaapNoncompeteAgreementsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapNoncompeteAgreementsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SoftwareDevelopmentMember" xlink:label="loc_us-gaapSoftwareDevelopmentMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapSoftwareDevelopmentMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IntellectualPropertyMember" xlink:label="loc_us-gaapIntellectualPropertyMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapIntellectualPropertyMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PatentsMember" xlink:label="loc_us-gaapPatentsMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapPatentsMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InProcessResearchAndDevelopmentMember" xlink:label="loc_us-gaapInProcessResearchAndDevelopmentMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapInProcessResearchAndDevelopmentMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsGross_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsGross_170" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsAccumulatedAmortization_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsAccumulatedAmortization_170" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsNet_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsNet_170" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetUsefulLife_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetUsefulLife_170" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/GoodwillAndIntangibleAssetsEstimatedAmortizationExpenseDetails" xlink:title="00000041 - Disclosure - Goodwill and Intangible Assets: Estimated amortization expense (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/GoodwillAndIntangibleAssetsDetailsNarrative" xlink:title="00000042 - Disclosure - Goodwill and Intangible Assets (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InProcessResearchAndDevelopmentMember" xlink:label="loc_us-gaapInProcessResearchAndDevelopmentMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="loc_us-gaapInProcessResearchAndDevelopmentMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_HDSMember" xlink:label="loc_GNBTHDSMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTHDSMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_RegentysMember" xlink:label="loc_GNBTRegentysMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTRegentysMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OlaregenMember" xlink:label="loc_GNBTOlaregenMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTOlaregenMember_30" xlink:type="arc" order="32" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaapAmortizationOfIntangibleAssets_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAmortizationOfIntangibleAssets_90" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsGross_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsGross_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaapGoodwill_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapGoodwill_90" xlink:type="arc" order="2" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NotesPayableDetails" xlink:title="00000043 - Disclosure - Notes Payable (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NotesPayableDetails1" xlink:title="00000044 - Disclosure - Notes Payable (Details 1)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NotesPayableDetailsNarrative" xlink:title="00000045 - Disclosure - Notes Payable (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SecuritiesPurchaseAgreementsMember" xlink:label="loc_GNBTSecuritiesPurchaseAgreementsMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_GNBTSecuritiesPurchaseAgreementsMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InvestorsMember" xlink:label="loc_GNBTInvestorsMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTInvestorsMember_60" xlink:type="arc" order="62" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InvestorMember" xlink:label="loc_us-gaapInvestorMember_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_us-gaapInvestorMember_70" xlink:type="arc" order="72" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_LenderMember" xlink:label="loc_GNBTLenderMember_320" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTLenderMember_320" xlink:type="arc" order="321" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaapLongtermDebtTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapLongtermDebtTypeAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaapLongtermDebtTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapLongtermDebtTypeAxis" xlink:to="loc_us-gaapLongtermDebtTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaapLongtermDebtTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapLongtermDebtTypeAxis" xlink:to="loc_us-gaapLongtermDebtTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_TwoNotesMember" xlink:label="loc_GNBTTwoNotesMember_270" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongtermDebtTypeDomain" xlink:to="loc_GNBTTwoNotesMember_270" xlink:type="arc" order="271" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PromissoryNoteMember" xlink:label="loc_GNBTPromissoryNoteMember_330" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapLongtermDebtTypeDomain" xlink:to="loc_GNBTPromissoryNoteMember_330" xlink:type="arc" order="332" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaapFinancialInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapFinancialInstrumentAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaapTransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapFinancialInstrumentAxis" xlink:to="loc_us-gaapTransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaapTransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapFinancialInstrumentAxis" xlink:to="loc_us-gaapTransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PrincipalMember" xlink:label="loc_GNBTPrincipalMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapTransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="loc_GNBTPrincipalMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InterestMember" xlink:label="loc_GNBTInterestMember_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapTransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="loc_GNBTInterestMember_220" xlink:type="arc" order="221" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_280" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_280" xlink:type="arc" order="281" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_290" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_290" xlink:type="arc" order="291" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_RegentysMember" xlink:label="loc_GNBTRegentysMember_160" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTRegentysMember_160" xlink:type="arc" order="161" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="loc_us-gaapSubsidiarySaleOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapSubsidiarySaleOfStockAxis" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="loc_us-gaapSaleOfStockNameOfTransactionDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapSubsidiarySaleOfStockAxis" xlink:to="loc_us-gaapSaleOfStockNameOfTransactionDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="loc_us-gaapSaleOfStockNameOfTransactionDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSubsidiarySaleOfStockAxis" xlink:to="loc_us-gaapSaleOfStockNameOfTransactionDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SubsidiariesMember" xlink:label="loc_srtSubsidiariesMember_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSaleOfStockNameOfTransactionDomain" xlink:to="loc_srtSubsidiariesMember_180" xlink:type="arc" order="181" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaapDebtInstrumentCarryingAmount_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentCarryingAmount_370" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PurchasePriceOfNote" xlink:label="loc_GNBTPurchasePriceOfNote_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPurchasePriceOfNote_370" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_InvestorFee" xlink:label="loc_GNBTInvestorFee_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTInvestorFee_370" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NotesReceivableRelatedParties" xlink:label="loc_us-gaapNotesReceivableRelatedParties_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNotesReceivableRelatedParties_370" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="loc_us-gaapDebtInstrumentInterestRateEffectivePercentage_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateEffectivePercentage_370" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_370" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="loc_us-gaapDebtInstrumentMaturityDate_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentMaturityDate_370" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PaymentOfPromissoryNote" xlink:label="loc_GNBTPaymentOfPromissoryNote_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPaymentOfPromissoryNote_370" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentIncreaseAccruedInterest" xlink:label="loc_us-gaapDebtInstrumentIncreaseAccruedInterest_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentIncreaseAccruedInterest_370" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentSharesIssued1_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentSharesIssued1_370" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentAmount1_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentAmount1_370" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaapDerivativeFairValueOfDerivativeLiability_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDerivativeFairValueOfDerivativeLiability_370" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="loc_us-gaapDebtInstrumentUnamortizedDiscount_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtInstrumentUnamortizedDiscount_370" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NotesPayableCurrent" xlink:label="loc_us-gaapNotesPayableCurrent_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNotesPayableCurrent_370" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessExitCosts1" xlink:label="loc_us-gaapBusinessExitCosts1_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapBusinessExitCosts1_370" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromLoans" xlink:label="loc_us-gaapProceedsFromLoans_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromLoans_370" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentWarrantsOrOptionsIssued1_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentWarrantsOrOptionsIssued1_370" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ExercisePrice" xlink:label="loc_GNBTExercisePrice_370" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTExercisePrice_370" xlink:type="arc" order="17" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/DerivativeLiabilityDetails" xlink:title="00000046 - Disclosure - Derivative Liability (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="loc_us-gaapFairValueByLiabilityClassAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapFairValueByLiabilityClassAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaapFairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapFairValueByLiabilityClassAxis" xlink:to="loc_us-gaapFairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="loc_us-gaapFairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapFairValueByLiabilityClassAxis" xlink:to="loc_us-gaapFairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DerivativeLiabilityConvertibleNotesMember" xlink:label="loc_GNBTDerivativeLiabilityConvertibleNotesMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:to="loc_GNBTDerivativeLiabilityConvertibleNotesMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DerivativeLiabilityWarrantsMember" xlink:label="loc_GNBTDerivativeLiabilityWarrantsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapFairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:to="loc_GNBTDerivativeLiabilityWarrantsMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaapDerivativeLiabilities_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDerivativeLiabilities_40" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInDerivativeLiabilities" xlink:label="loc_us-gaapIncreaseDecreaseInDerivativeLiabilities_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIncreaseDecreaseInDerivativeLiabilities_40" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ChangeInFairValue" xlink:label="loc_GNBTChangeInFairValue_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTChangeInFairValue_40" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ChangeDueToConversionExercise" xlink:label="loc_GNBTChangeDueToConversionExercise_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTChangeDueToConversionExercise_40" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/StockholdersEquityDetails" xlink:title="00000047 - Disclosure - Stockholders&apos; Equity (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/StockholdersEquityDetailsNarrative" xlink:title="00000048 - Disclosure - Stockholders&apos; Equity (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_VendorsMember" xlink:label="loc_GNBTVendorsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTVendorsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OasisCapitalLLCMember" xlink:label="loc_GNBTOasisCapitalLLCMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTOasisCapitalLLCMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AccreditedInvestorsMember" xlink:label="loc_GNBTAccreditedInvestorsMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTAccreditedInvestorsMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="loc_us-gaapTypeOfArrangementAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapTypeOfArrangementAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapTypeOfArrangementAxis" xlink:to="loc_us-gaapArrangementsAndNonarrangementTransactionsMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_EquityPurchaseAgreementMember" xlink:label="loc_GNBTEquityPurchaseAgreementMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_GNBTEquityPurchaseAgreementMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SecurityPurchaseAgreementMember" xlink:label="loc_GNBTSecurityPurchaseAgreementMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_GNBTSecurityPurchaseAgreementMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ShareExchangeAgreementMember" xlink:label="loc_GNBTShareExchangeAgreementMember_130" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapArrangementsAndNonarrangementTransactionsMember" xlink:to="loc_GNBTShareExchangeAgreementMember_130" xlink:type="arc" order="131" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_MedisourceMember" xlink:label="loc_GNBTMedisourceMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTMedisourceMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PantheonMember" xlink:label="loc_GNBTPantheonMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTPantheonMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OlaregenMember" xlink:label="loc_GNBTOlaregenMember_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTOlaregenMember_110" xlink:type="arc" order="111" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NGIOMember" xlink:label="loc_GNBTNGIOMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTNGIOMember_120" xlink:type="arc" order="121" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_RegentysMember" xlink:label="loc_GNBTRegentysMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_GNBTRegentysMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesAWarrantsMember" xlink:label="loc_GNBTSeriesAWarrantsMember_170" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesAWarrantsMember_170" xlink:type="arc" order="173" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesBWarrantsMember" xlink:label="loc_GNBTSeriesBWarrantsMember_180" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesBWarrantsMember_180" xlink:type="arc" order="183" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesCWarrantsMember" xlink:label="loc_GNBTSeriesCWarrantsMember_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesCWarrantsMember_190" xlink:type="arc" order="193" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesDWarrantsMember" xlink:label="loc_GNBTSeriesDWarrantsMember_200" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesDWarrantsMember_200" xlink:type="arc" order="203" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaapAllocatedShareBasedCompensationExpense_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAllocatedShareBasedCompensationExpense_260" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_260" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_260" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesOther_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesOther_260" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueOther" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueOther_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueOther_260" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_CommonStockToBeIssued" xlink:label="loc_GNBTCommonStockToBeIssued_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTCommonStockToBeIssued_260" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentSharesIssued1_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentSharesIssued1_260" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:label="loc_us-gaapDebtConversionConvertedInstrumentAmount1_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtConversionConvertedInstrumentAmount1_260" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLossOnDerivative" xlink:label="loc_us-gaapDerivativeLossOnDerivative_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDerivativeLossOnDerivative_260" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_260" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionSharePrice" xlink:label="loc_us-gaapBusinessAcquisitionSharePrice_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapBusinessAcquisitionSharePrice_260" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_CancellationOfCommonStock" xlink:label="loc_GNBTCancellationOfCommonStock_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTCancellationOfCommonStock_260" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NumberOfSharesExchanged" xlink:label="loc_GNBTNumberOfSharesExchanged_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTNumberOfSharesExchanged_260" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_LoiTerms" xlink:label="loc_GNBTLoiTerms_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTLoiTerms_260" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding_260" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaapCommonStockSharesIssued_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesIssued_260" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_CommonStockPurchased" xlink:label="loc_GNBTCommonStockPurchased_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTCommonStockPurchased_260" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="loc_us-gaapSaleOfStockNumberOfSharesIssuedInTransaction_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSaleOfStockNumberOfSharesIssuedInTransaction_260" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:label="loc_us-gaapSaleOfStockConsiderationReceivedOnTransaction_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSaleOfStockConsiderationReceivedOnTransaction_260" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaapProceedsFromIssuanceOfCommonStock_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromIssuanceOfCommonStock_260" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AttorneysFees" xlink:label="loc_GNBTAttorneysFees_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTAttorneysFees_260" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharesIssuedPricePerShare" xlink:label="loc_us-gaapSharesIssuedPricePerShare_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesIssuedPricePerShare_260" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="loc_us-gaapCommonStockCapitalSharesReservedForFutureIssuance_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockCapitalSharesReservedForFutureIssuance_260" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightUnissued" xlink:label="loc_us-gaapClassOfWarrantOrRightUnissued_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightUnissued_260" xlink:type="arc" order="23" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_260" xlink:type="arc" order="24" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NoncontrollingInterest" xlink:label="loc_GNBTNoncontrollingInterest_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTNoncontrollingInterest_260" xlink:type="arc" order="25" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PercentageOfNoncontrollingInterest" xlink:label="loc_GNBTPercentageOfNoncontrollingInterest_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPercentageOfNoncontrollingInterest_260" xlink:type="arc" order="26" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DeemedDividend" xlink:label="loc_GNBTDeemedDividend_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTDeemedDividend_260" xlink:type="arc" order="27" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_DecreaseInAccumulatedDeficit" xlink:label="loc_GNBTDecreaseInAccumulatedDeficit_260" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTDecreaseInAccumulatedDeficit_260" xlink:type="arc" order="28" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/RedeemableNon-controllingInterestDetailsNarrative" xlink:title="00000049 - Disclosure - Redeemable Non-Controlling Interest (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Stock-basedCompensation-CommonStockOptionsGrantedForfeitedOrExpiredAndExercisedDetails" xlink:title="00000050 - Disclosure - Stock-Based Compensation - Common stock options granted, forfeited or expired and exercised (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Stock-basedCompensation-Non-vestedOptionsGrantedForfeitedOrExpiredAndExercisedDetails" xlink:title="00000051 - Disclosure - Stock-Based Compensation - Non-vested Options granted, forfeited or expired and exercised (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NonVestedOptionsMember" xlink:label="loc_GNBTNonVestedOptionsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTNonVestedOptionsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares_20" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_20" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirations" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirations_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExpirations_20" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares_20" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_20" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue_20" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_20" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_20" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCancelledWeightedAverageGrantDateFairValue" xlink:label="loc_GNBTShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCancelledWeightedAverageGrantDateFairValue_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCancelledWeightedAverageGrantDateFairValue_20" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_20" xlink:type="arc" order="10" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Stock-basedCompensation-FairValueAssumptionsUsedInBlack-scholesOption-pricingDetails" xlink:title="00000052 - Disclosure - Stock-Based Compensation - Fair value assumptions used in Black-Scholes option-pricing (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice_60" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_60" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_60" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_60" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_60" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaapSharePrice_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharePrice_60" xlink:type="arc" order="5" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/Stock-basedCompensationDetailsNarrative" xlink:title="00000053 - Disclosure - Stock-Based Compensation (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockOptionMember" xlink:label="loc_us-gaapStockOptionMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaapStockOptionMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_0" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaapPlanNameAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapPlanNameAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaapPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPlanNameAxis" xlink:to="loc_us-gaapPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaapPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPlanNameAxis" xlink:to="loc_us-gaapPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_StockOptionPlan2006Member" xlink:label="loc_GNBTStockOptionPlan2006Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_GNBTStockOptionPlan2006Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_StockOptionPlan2017Member" xlink:label="loc_GNBTStockOptionPlan2017Member_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_GNBTStockOptionPlan2017Member_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_StockOptionPlan2019Member" xlink:label="loc_GNBTStockOptionPlan2019Member_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPlanNameDomain" xlink:to="loc_GNBTStockOptionPlan2019Member_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OfficersMember" xlink:label="loc_GNBTOfficersMember_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTOfficersMember_100" xlink:type="arc" order="102" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="loc_us-gaapCommonStockCapitalSharesReservedForFutureIssuance_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockCapitalSharesReservedForFutureIssuance_120" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPeriodIncreaseDecrease" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPeriodIncreaseDecrease_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingPeriodIncreaseDecrease_120" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_MarketValue" xlink:label="loc_GNBTMarketValue_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTMarketValue_120" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_120" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensation_120" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaapEmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapEmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_120" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaapEmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapEmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_120" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_120" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_120" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_120" xlink:type="arc" order="9" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/WarrantsDetails" xlink:title="00000054 - Disclosure - Warrants (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesAWarrantsMember" xlink:label="loc_GNBTSeriesAWarrantsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesAWarrantsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesBWarrantsMember" xlink:label="loc_GNBTSeriesBWarrantsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesBWarrantsMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesCWarrantsMember" xlink:label="loc_GNBTSeriesCWarrantsMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesCWarrantsMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_WarrantsMember" xlink:label="loc_GNBTWarrantsMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTWarrantsMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_WarrantsIssued" xlink:label="loc_GNBTWarrantsIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTWarrantsIssued_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AdditionalWarrantsIssued" xlink:label="loc_GNBTAdditionalWarrantsIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTAdditionalWarrantsIssued_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ExercisePrice" xlink:label="loc_GNBTExercisePrice_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTExercisePrice_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="loc_us-gaapClassOfWarrantOrRightOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightOutstanding_50" xlink:type="arc" order="4" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/WarrantsDetails1" xlink:title="00000055 - Disclosure - Warrants (Details 1)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/WarrantsDetailsNarrative" xlink:title="00000056 - Disclosure - Warrants (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaapAwardTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAwardTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAwardTypeAxis" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_SeriesDWarrantsMember" xlink:label="loc_GNBTSeriesDWarrantsMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_GNBTSeriesDWarrantsMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="loc_us-gaapClassOfWarrantOrRightOutstanding_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightOutstanding_70" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightUnissued" xlink:label="loc_us-gaapClassOfWarrantOrRightUnissued_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightUnissued_70" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NumberOfWarrantsIssuedAndExercised" xlink:label="loc_GNBTNumberOfWarrantsIssuedAndExercised_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTNumberOfWarrantsIssuedAndExercised_70" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_70" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/NetIncomePerShareEps-ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareDetails" xlink:title="00000057 - Disclosure - Net Income Per Share (EPS) - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaapAntidilutiveSecuritiesNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="loc_us-gaapAntidilutiveSecuritiesNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaapAntidilutiveSecuritiesNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="loc_us-gaapAntidilutiveSecuritiesNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ConvertibleDebtsMember" xlink:label="loc_GNBTConvertibleDebtsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAntidilutiveSecuritiesNameDomain" xlink:to="loc_GNBTConvertibleDebtsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_StockOptionsMember" xlink:label="loc_GNBTStockOptionsMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAntidilutiveSecuritiesNameDomain" xlink:to="loc_GNBTStockOptionsMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_WarrantsMember" xlink:label="loc_GNBTWarrantsMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapAntidilutiveSecuritiesNameDomain" xlink:to="loc_GNBTWarrantsMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_90" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/IncomeTaxesDetailsNarrative" xlink:title="00000058 - Disclosure - Income Taxes (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_GenerexPharmaceuticalsMember" xlink:label="loc_GNBTGenerexPharmaceuticalsMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTGenerexPharmaceuticalsMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_NGIOMember" xlink:label="loc_GNBTNGIOMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTNGIOMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_RegentysMember" xlink:label="loc_GNBTRegentysMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTRegentysMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OlaregenMember" xlink:label="loc_GNBTOlaregenMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTOlaregenMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_VenetoMember" xlink:label="loc_GNBTVenetoMember_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTVenetoMember_70" xlink:type="arc" order="71" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PretaxGainOrLossArisingFromDomesticOperations" xlink:label="loc_GNBTPretaxGainOrLossArisingFromDomesticOperations_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPretaxGainOrLossArisingFromDomesticOperations_90" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_PretaxLossesArisingFromForeignOperations" xlink:label="loc_GNBTPretaxLossesArisingFromForeignOperations_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTPretaxLossesArisingFromForeignOperations_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="loc_us-gaapOperatingLossCarryforwards_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOperatingLossCarryforwards_90" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" xlink:label="loc_us-gaapIncreaseDecreaseInDeferredIncomeTaxes_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapIncreaseDecreaseInDeferredIncomeTaxes_90" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://generex.com/role/SubsequentEventsDetailsNarrative" xlink:title="00000059 - Disclosure - Subsequent Events (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaapSubsequentEventTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapSubsequentEventTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaapSubsequentEventMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSubsequentEventTypeDomain" xlink:to="loc_us-gaapSubsequentEventMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_OasisMember" xlink:label="loc_GNBTOasisMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_GNBTOasisMember_0" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_60" xlink:type="arc" order="62" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_70" xlink:type="arc" order="72" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_90" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaapProceedsFromStockOptionsExercised_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromStockOptionsExercised_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_AgreementDescription" xlink:label="loc_GNBTAgreementDescription_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTAgreementDescription_90" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ContractedAmount" xlink:label="loc_GNBTContractedAmount_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTContractedAmount_90" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="gnbt-20201031.xsd#GNBT_ProjectCost" xlink:label="loc_GNBTProjectCost_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_GNBTProjectCost_90" xlink:type="arc" order="4" />
    </link:definitionLink>
</link:linkbase>


