<?xml version="1.0" encoding="us-ascii"?>
<!-- Created by Merrill Corporation -->
<!--XBRL document created with Merrill Bridge Powered by Crossfire 5.9.163.0 -->
<!--Based on XBRL 2.1-->
<!--Created on: 7/25/2014 1:05:25 PM-->
<!--Modified on: 7/25/2014 1:05:25 PM-->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#StatementConsolidatedBalanceSheets" roleURI="http://www.unither.com/role/StatementConsolidatedBalanceSheets" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#StatementConsolidatedStatementsOfOperations" roleURI="http://www.unither.com/role/StatementConsolidatedStatementsOfOperations" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#StatementConsolidatedStatementsOfComprehensiveIncome" roleURI="http://www.unither.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#StatementConsolidatedStatementsOfCashFlows" roleURI="http://www.unither.com/role/StatementConsolidatedStatementsOfCashFlows" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureInventoriesDetails" roleURI="http://www.unither.com/role/DisclosureInventoriesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureFairValueMeasurementsDetails" roleURI="http://www.unither.com/role/DisclosureFairValueMeasurementsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureInvestmentsDetails" roleURI="http://www.unither.com/role/DisclosureInvestmentsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureInvestmentsDetails2" roleURI="http://www.unither.com/role/DisclosureInvestmentsDetails2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureInvestmentsDetails3" roleURI="http://www.unither.com/role/DisclosureInvestmentsDetails3" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureInvestmentsDetails4" roleURI="http://www.unither.com/role/DisclosureInvestmentsDetails4" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureGoodwillAndOtherIntangibleAssetsDetails" roleURI="http://www.unither.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureGoodwillAndOtherIntangibleAssetsDetailsCalc2" roleURI="http://www.unither.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetailsCalc2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureSupplementalExecutiveRetirementPlanDetails" roleURI="http://www.unither.com/role/DisclosureSupplementalExecutiveRetirementPlanDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureSupplementalExecutiveRetirementPlanDetails2" roleURI="http://www.unither.com/role/DisclosureSupplementalExecutiveRetirementPlanDetails2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureShareTrackingAwardPlansDetails2" roleURI="http://www.unither.com/role/DisclosureShareTrackingAwardPlansDetails2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureDebtDetails" roleURI="http://www.unither.com/role/DisclosureDebtDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureTemporaryEquityDetails" roleURI="http://www.unither.com/role/DisclosureTemporaryEquityDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureStockholdersEquityDetails" roleURI="http://www.unither.com/role/DisclosureStockholdersEquityDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureAccumulatedOtherComprehensiveLossDetails" roleURI="http://www.unither.com/role/DisclosureAccumulatedOtherComprehensiveLossDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureSegmentInformationDetails" roleURI="http://www.unither.com/role/DisclosureSegmentInformationDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="uthr-20140630.xsd#DisclosureSummaryOfSignificantAccountingPoliciesDetails2Calc2" roleURI="http://www.unither.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails2Calc2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <calculationLink xlink:role="http://www.unither.com/role/StatementConsolidatedBalanceSheets" xlink:type="extended" xlink:title="00100 - Statement - CONSOLIDATED BALANCE SHEETS" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsCurrent_635418903214067809" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635418903214067809" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_635418903214067809" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesCurrent" xlink:label="us-gaap_HeldToMaturitySecuritiesCurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635418903214067809" xlink:to="us-gaap_HeldToMaturitySecuritiesCurrent_635418903214067809" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="us-gaap_AccountsReceivableNetCurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635418903214067809" xlink:to="us-gaap_AccountsReceivableNetCurrent_635418903214067809" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InventoryNet" xlink:label="us-gaap_InventoryNet_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635418903214067809" xlink:to="us-gaap_InventoryNet_635418903214067809" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="us-gaap_OtherAssetsCurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635418903214067809" xlink:to="us-gaap_OtherAssetsCurrent_635418903214067809" order="5" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MarketableSecuritiesNoncurrent" xlink:label="us-gaap_MarketableSecuritiesNoncurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_MarketableSecuritiesNoncurrent_635418903214067809" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RestrictedCashAndInvestmentsNoncurrent" xlink:label="us-gaap_RestrictedCashAndInvestmentsNoncurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_RestrictedCashAndInvestmentsNoncurrent_635418903214067809" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_IntangibleAssetsNetIncludingGoodwill_635418903214067809" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_635418903214067809" order="5" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNetNoncurrent" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNetNoncurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_DeferredTaxAssetsLiabilitiesNetNoncurrent_635418903214067809" order="6" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="us-gaap_OtherAssetsNoncurrent_635418903214067809" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_OtherAssetsNoncurrent_635418903214067809" order="7" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_Liabilities_635418903214077810" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities_635418903214077810" xlink:to="us-gaap_LiabilitiesCurrent_635418903214077810" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635418903214077810" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_635418903214077810" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConvertibleNotesPayableCurrent" xlink:label="us-gaap_ConvertibleNotesPayableCurrent_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635418903214077810" xlink:to="us-gaap_ConvertibleNotesPayableCurrent_635418903214077810" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_ShareTrackingAwardPlans" xlink:label="uthr_ShareTrackingAwardPlans_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635418903214077810" xlink:to="uthr_ShareTrackingAwardPlans_635418903214077810" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NotesPayableCurrent" xlink:label="us-gaap_NotesPayableCurrent_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635418903214077810" xlink:to="us-gaap_NotesPayableCurrent_635418903214077810" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="us-gaap_OtherLiabilitiesCurrent_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635418903214077810" xlink:to="us-gaap_OtherLiabilitiesCurrent_635418903214077810" order="5" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongTermNotesPayable" xlink:label="us-gaap_LongTermNotesPayable_635418903214077810" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities_635418903214077810" xlink:to="us-gaap_LongTermNotesPayable_635418903214077810" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities_635418903214077810" xlink:to="us-gaap_OtherLiabilitiesNoncurrent_635418903214087811" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_635418903214087811" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_StockholdersEquity_635418903214087811" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635418903214087811" xlink:to="us-gaap_PreferredStockValue_635418903214087811" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635418903214087811" xlink:to="us-gaap_CommonStockValue_635418903214087811" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635418903214087811" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock_635418903214087811" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635418903214087811" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_635418903214087811" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="us-gaap_TreasuryStockValue_635418903214087811" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635418903214087811" xlink:to="us-gaap_TreasuryStockValue_635418903214087811" order="5" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635418903214087811" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_635418903214097812" order="6" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/StatementConsolidatedStatementsOfOperations" xlink:type="extended" xlink:title="00200 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635418903214097812" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635418903214097812" xlink:to="us-gaap_OperatingIncomeLoss_635418903214097812" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Revenues" xlink:label="us-gaap_Revenues_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss_635418903214097812" xlink:to="us-gaap_Revenues_635418903214097812" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="us-gaap_SalesRevenueGoodsNet_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Revenues_635418903214097812" xlink:to="us-gaap_SalesRevenueGoodsNet_635418903214097812" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherSalesRevenueNet" xlink:label="us-gaap_OtherSalesRevenueNet_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Revenues_635418903214097812" xlink:to="us-gaap_OtherSalesRevenueNet_635418903214097812" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="us-gaap_CostsAndExpenses_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss_635418903214097812" xlink:to="us-gaap_CostsAndExpenses_635418903214097812" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="us-gaap_ResearchAndDevelopmentExpense_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses_635418903214097812" xlink:to="us-gaap_ResearchAndDevelopmentExpense_635418903214097812" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses_635418903214097812" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense_635418903214097812" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="us-gaap_CostOfGoodsSold_635418903214097812" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses_635418903214097812" xlink:to="us-gaap_CostOfGoodsSold_635418903214097812" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635418903214097812" xlink:to="us-gaap_NonoperatingIncomeExpense_635418903214107813" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="us-gaap_InvestmentIncomeInterest_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense_635418903214107813" xlink:to="us-gaap_InvestmentIncomeInterest_635418903214107813" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense_635418903214107813" xlink:to="us-gaap_InterestExpense_635418903214107813" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense_635418903214107813" xlink:to="us-gaap_OtherNonoperatingIncomeExpense_635418903214107813" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_IncomeTaxExpenseBenefit_635418903214107813" order="2" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended" xlink:title="00300 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_635418903214107813" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_635418903214107813" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_635418903214107813" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_635418903214107813" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax_635418903214117814" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_635418903214117814" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_OtherComprehensiveIncomeLossAmortizationGainLossAndNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax" xlink:label="uthr_OtherComprehensiveIncomeLossAmortizationGainLossAndNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_635418903214107813" xlink:to="uthr_OtherComprehensiveIncomeLossAmortizationGainLossAndNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax_635418903214117814" order="3" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_635418903214107813" xlink:to="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_635418903214117814" order="3" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/StatementConsolidatedStatementsOfCashFlows" xlink:type="extended" xlink:title="00400 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_635418903214117814" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="us-gaap_DepreciationDepletionAndAmortization_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_DepreciationDepletionAndAmortization_635418903214117814" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_ProvisionForDoubtfulAccountsAndInventoryWritedown" xlink:label="uthr_ProvisionForDoubtfulAccountsAndInventoryWritedown_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="uthr_ProvisionForDoubtfulAccountsAndInventoryWritedown_635418903214117814" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_IncomeTaxCashFlows" xlink:label="uthr_IncomeTaxCashFlows_635418903214117814" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="uthr_IncomeTaxCashFlows_635418903214117814" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_ShareBasedCompensation_635418903214127815" order="5" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_AmortizationOfFinancingCostsAndDiscounts_635418903214127815" order="6" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:label="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_635418903214127815" order="7" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="us-gaap_OtherNoncashIncomeExpense_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_OtherNoncashIncomeExpense_635418903214127815" order="8" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities" xlink:label="us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_635418903214127815" order="9" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_IncreaseDecreaseInAccountsReceivable_635418903214127815" order="10" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="us-gaap_IncreaseDecreaseInInventories_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_IncreaseDecreaseInInventories_635418903214127815" order="11" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_IncreaseDecreaseInInsuranceProceedsReceivable" xlink:label="uthr_IncreaseDecreaseInInsuranceProceedsReceivable_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="uthr_IncreaseDecreaseInInsuranceProceedsReceivable_635418903214127815" order="12" use="optional" weight="-1" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingAssets_635418903214127815" order="13" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_635418903214127815" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_635418903214127815" order="14" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635418903214117814" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_635418903214137816" order="15" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635418903214137816" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_635418903214137816" order="1" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PaymentsToAcquireHeldToMaturitySecurities" xlink:label="us-gaap_PaymentsToAcquireHeldToMaturitySecurities_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_PaymentsToAcquireHeldToMaturitySecurities_635418903214137816" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_635418903214137816" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PaymentsToAcquireInvestments" xlink:label="us-gaap_PaymentsToAcquireInvestments_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_PaymentsToAcquireInvestments_635418903214137816" order="4" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_PaymentsForRepurchaseOfCommonStock_635418903214137816" order="1" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:label="us-gaap_ProceedsFromLinesOfCredit_635418903214137816" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_ProceedsFromLinesOfCredit_635418903214137816" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_ProceedsFromStockOptionsExercised_635418903214147817" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans_635418903214147817" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635418903214137816" xlink:to="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_635418903214147817" order="5" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" xlink:label="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:to="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations_635418903214147817" order="4" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureInventoriesDetails" xlink:type="extended" xlink:title="40301 - Disclosure - Inventories (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InventoryNet" xlink:label="us-gaap_InventoryNet" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InventoryRawMaterialsNetOfReserves" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InventoryNet" xlink:to="us-gaap_InventoryRawMaterialsNetOfReserves_635418903214147817" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InventoryWorkInProcessNetOfReserves" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InventoryNet" xlink:to="us-gaap_InventoryWorkInProcessNetOfReserves_635418903214147817" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves_635418903214147817" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InventoryNet" xlink:to="us-gaap_InventoryFinishedGoodsNetOfReserves_635418903214147817" order="3" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureFairValueMeasurementsDetails" xlink:type="extended" xlink:title="40401 - Disclosure - Fair Value Measurements (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="us-gaap_AssetsFairValueDisclosure" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MoneyMarketFundsAtCarryingValue" xlink:label="us-gaap_MoneyMarketFundsAtCarryingValue_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsFairValueDisclosure" xlink:to="us-gaap_MoneyMarketFundsAtCarryingValue_635418903214157818" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsFairValueDisclosure" xlink:to="us-gaap_HeldToMaturitySecuritiesFairValue_635418903214157818" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="us-gaap_LiabilitiesFairValueDisclosure" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConvertibleDebtFairValueDisclosures" xlink:label="us-gaap_ConvertibleDebtFairValueDisclosures_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesFairValueDisclosure" xlink:to="us-gaap_ConvertibleDebtFairValueDisclosures_635418903214157818" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_BusinessAcquisitionContingentConsiderationFairValueDisclosure" xlink:label="uthr_BusinessAcquisitionContingentConsiderationFairValueDisclosure_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesFairValueDisclosure" xlink:to="uthr_BusinessAcquisitionContingentConsiderationFairValueDisclosure_635418903214157818" order="2" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureInvestmentsDetails" xlink:type="extended" xlink:title="40501 - Disclosure - Investments (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecurities" xlink:label="us-gaap_HeldToMaturitySecurities_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesFairValue" xlink:to="us-gaap_HeldToMaturitySecurities_635418903214157818" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain" xlink:label="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesFairValue" xlink:to="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_635418903214157818" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss" xlink:label="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesFairValue" xlink:to="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_635418903214157818" order="3" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureInvestmentsDetails2" xlink:type="extended" xlink:title="40502 - Disclosure - Investments (Details 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecurities" xlink:label="us-gaap_HeldToMaturitySecurities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesCurrent" xlink:label="us-gaap_HeldToMaturitySecuritiesCurrent_635418903214157818" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecurities" xlink:to="us-gaap_HeldToMaturitySecuritiesCurrent_635418903214157818" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesNoncurrent" xlink:label="us-gaap_HeldToMaturitySecuritiesNoncurrent_635418903214167819" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecurities" xlink:to="us-gaap_HeldToMaturitySecuritiesNoncurrent_635418903214167819" order="2" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureInvestmentsDetails3" xlink:type="extended" xlink:title="40503 - Disclosure - Investments (Details 3)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss" xlink:label="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="uthr_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_635418903214167819" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss" xlink:to="uthr_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_635418903214167819" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="uthr_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_635418903214167819" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="uthr_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss" xlink:to="uthr_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_635418903214167819" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_635418903214167819" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_635418903214167819" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_635418903214167819" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_635418903214167819" order="2" use="optional" weight="1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureInvestmentsDetails4" xlink:type="extended" xlink:title="40504 - Disclosure - Investments (Details 4)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecurities" xlink:label="us-gaap_HeldToMaturitySecurities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_635418903214167819" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecurities" xlink:to="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_635418903214167819" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesDebtMaturitiesInOneYearThroughTwoYearsNetCarryingAmount" xlink:label="uthr_HeldToMaturitySecuritiesDebtMaturitiesInOneYearThroughTwoYearsNetCarryingAmount_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecurities" xlink:to="uthr_HeldToMaturitySecuritiesDebtMaturitiesInOneYearThroughTwoYearsNetCarryingAmount_635418903214177820" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesDebtMaturitiesInThreeYearThroughFiveYearsNetCarryingAmount" xlink:label="uthr_HeldToMaturitySecuritiesDebtMaturitiesInThreeYearThroughFiveYearsNetCarryingAmount_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecurities" xlink:to="uthr_HeldToMaturitySecuritiesDebtMaturitiesInThreeYearThroughFiveYearsNetCarryingAmount_635418903214177820" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesFairValue" xlink:to="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_635418903214177820" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesDebtMaturitiesInOneYearThroughTwoYearsFairValue" xlink:label="uthr_HeldToMaturitySecuritiesDebtMaturitiesInOneYearThroughTwoYearsFairValue_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesFairValue" xlink:to="uthr_HeldToMaturitySecuritiesDebtMaturitiesInOneYearThroughTwoYearsFairValue_635418903214177820" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_HeldToMaturitySecuritiesDebtMaturitiesInThreeYearThroughFiveYearsFairValue" xlink:label="uthr_HeldToMaturitySecuritiesDebtMaturitiesInThreeYearThroughFiveYearsFairValue_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_HeldToMaturitySecuritiesFairValue" xlink:to="uthr_HeldToMaturitySecuritiesDebtMaturitiesInThreeYearThroughFiveYearsFairValue_635418903214177820" order="3" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetails" xlink:type="extended" xlink:title="40601 - Disclosure - Goodwill and Other Intangible Assets (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross_635418903214177820" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_635418903214177820" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_635418903214177820" order="2" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetailsCalc2" xlink:type="extended" xlink:title="40602 - Disclosure - Goodwill and Other Intangible Assets (Details) (Calc 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_GoodwillAndOtherIntangiblesAssetsGross" xlink:label="uthr_GoodwillAndOtherIntangiblesAssetsGross" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillGross" xlink:label="us-gaap_GoodwillGross_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="uthr_GoodwillAndOtherIntangiblesAssetsGross" xlink:to="us-gaap_GoodwillGross_635418903214187821" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="uthr_GoodwillAndOtherIntangiblesAssetsGross" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross_635418903214187821" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:to="us-gaap_Goodwill_635418903214187821" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet_635418903214187821" order="2" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureSupplementalExecutiveRetirementPlanDetails" xlink:type="extended" xlink:title="40701 - Disclosure - Supplemental Executive Retirement Plan (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="us-gaap_DefinedBenefitPlanServiceCost_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanServiceCost_635418903214187821" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="us-gaap_DefinedBenefitPlanInterestCost_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanInterestCost_635418903214187821" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_635418903214187821" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_635418903214187821" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_635418903214187821" order="4" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureSupplementalExecutiveRetirementPlanDetails2" xlink:type="extended" xlink:title="40702 - Disclosure - Supplemental Executive Retirement Plan (Details 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax_635418903214197822" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax_635418903214197822" xlink:to="us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax_635418903214197822" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax_635418903214197822" xlink:to="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_635418903214197822" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_635418903214197822" order="2" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureShareTrackingAwardPlansDetails2" xlink:type="extended" xlink:title="40802 - Disclosure - Share Tracking Award Plans (Details 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:label="us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense_635418903214197822" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_635418903214197822" order="2" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureDebtDetails" xlink:type="extended" xlink:title="40901 - Disclosure - Debt (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InterestCostsIncurred" xlink:label="us-gaap_InterestCostsIncurred" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestCostsIncurred" xlink:to="us-gaap_InterestExpense_635418903214197822" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InterestCostsCapitalized" xlink:label="us-gaap_InterestCostsCapitalized_635418903214197822" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestCostsIncurred" xlink:to="us-gaap_InterestCostsCapitalized_635418903214197822" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:label="us-gaap_InterestExpenseDebt" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_InterestExpenseDebtExcludingAmortization" xlink:label="us-gaap_InterestExpenseDebtExcludingAmortization_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseDebt" xlink:to="us-gaap_InterestExpenseDebtExcludingAmortization_635418903214207823" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AmortizationOfDebtDiscountPremium" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseDebt" xlink:to="us-gaap_AmortizationOfDebtDiscountPremium_635418903214207823" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="us-gaap_DebtInstrumentCarryingAmount_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_DebtInstrumentCarryingAmount_635418903214207823" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount_635418903214207823" order="2" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureTemporaryEquityDetails" xlink:type="extended" xlink:title="41001 - Disclosure - Temporary Equity (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_TemporaryEquityUnamortizedDiscountOnConvertibleDebtReclassifiedFromAdditionalPaidInCapitalToTemporaryEquity" xlink:label="uthr_TemporaryEquityUnamortizedDiscountOnConvertibleDebtReclassifiedFromAdditionalPaidInCapitalToTemporaryEquity_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:to="uthr_TemporaryEquityUnamortizedDiscountOnConvertibleDebtReclassifiedFromAdditionalPaidInCapitalToTemporaryEquity_635418903214207823" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TemporaryEquityRedemptionValue" xlink:label="us-gaap_TemporaryEquityRedemptionValue_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:to="us-gaap_TemporaryEquityRedemptionValue_635418903214207823" order="2" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureStockholdersEquityDetails" xlink:type="extended" xlink:title="41101 - Disclosure - Stockholders' Equity (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_635418903214207823" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities" xlink:label="us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_635418903214207823" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_635418903214207823" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants" xlink:label="us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_635418903214217824" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_635418903214217824" order="4" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureAccumulatedOtherComprehensiveLossDetails" xlink:type="extended" xlink:title="41201 - Disclosure - Accumulated Other Comprehensive Loss (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_635418903214217824" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:label="us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_635418903214217824" order="2" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureSegmentInformationDetails" xlink:type="extended" xlink:title="41401 - Disclosure - Segment Information (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GrossProfit" xlink:label="us-gaap_GrossProfit" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="us-gaap_SalesRevenueGoodsNet_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_SalesRevenueGoodsNet_635418903214217824" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="us-gaap_CostOfGoodsSold_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_CostOfGoodsSold_635418903214217824" order="2" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_CostOfRevenues" xlink:label="uthr_CostOfRevenues_635418903214217824" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_GrossProfit" xlink:to="uthr_CostOfRevenues_635418903214217824" order="3" use="optional" weight="-1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.unither.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails2Calc2" xlink:type="extended" xlink:title="83500 - Disclosure - Summary of Significant Accounting Policies (Details 2) (Calc 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillGross" xlink:label="us-gaap_GoodwillGross_635418903214227825" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_GoodwillGross_635418903214227825" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill" />
    <loc xlink:type="locator" xlink:href="uthr-20140630.xsd#uthr_GoodwillAndOtherIntangiblesAssetsGross" xlink:label="uthr_GoodwillAndOtherIntangiblesAssetsGross_635418903214227825" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:to="uthr_GoodwillAndOtherIntangiblesAssetsGross_635418903214227825" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_635418903214227825" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_635418903214227825" order="2" use="optional" weight="-1" />
  </calculationLink>
</link:linkbase>


