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  <xs:element id="regn_McKessonCorporationMember" abstract="true" name="McKessonCorporationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_NonPerformanceBasedStockOptionsMember" abstract="true" name="NonPerformanceBasedStockOptionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_ArcalystNetProductSalesMember" abstract="true" name="ArcalystNetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_SalesMilestoneTwoMember" abstract="true" name="SalesMilestoneTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_BridgeFacilityMember" abstract="true" name="BridgeFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_UnrecognizedTaxBenefitsDecreaseResultingFromSettlementsWithTaxingAuthoritiesAndReductionResultingFromLapseOfApplicableStatuteOfLimitations" abstract="false" name="UnrecognizedTaxBenefitsDecreaseResultingFromSettlementsWithTaxingAuthoritiesAndReductionResultingFromLapseOfApplicableStatuteOfLimitations" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_LesseeFinanceLeaseLiabilityDebtFinancingCosts" abstract="false" name="LesseeFinanceLeaseLiabilityDebtFinancingCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_LossContingencyPercentageOfDamagesResponsibleFor" abstract="false" name="LossContingencyPercentageOfDamagesResponsibleFor" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_ClassificationOfInvestmentDomain" abstract="true" name="ClassificationOfInvestmentDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_ThreeIndividualCustomersMember" abstract="true" name="ThreeIndividualCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_IOAgreementMember" abstract="true" name="IOAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_EndingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" abstract="false" name="EndingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_ResearchCollaborationAndLicensingArrangementsTable" abstract="true" name="ResearchCollaborationAndLicensingArrangementsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_NumberOfVotesPerShare" abstract="false" name="NumberOfVotesPerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="regn_NetProfitInConnectionWithCommercializationMember" abstract="true" name="NetProfitInConnectionWithCommercializationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_PercentageOfRepaymentOfDevelopmentBalanceOutOfProfits" abstract="false" name="PercentageOfRepaymentOfDevelopmentBalanceOutOfProfits" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_ScheduleOfSalesRelatedDeductionsActivityTableTextBlock" abstract="false" name="ScheduleOfSalesRelatedDeductionsActivityTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="regn_StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" abstract="false" name="StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_IntelliaCollaborationAgreementMember" abstract="true" name="IntelliaCollaborationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_DebtInstrumentRedemptionPriceWithChangeInControlProvisionPercentage" abstract="false" name="DebtInstrumentRedemptionPriceWithChangeInControlProvisionPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_NumberOfNewlyIssuedSharesPurchased" abstract="false" name="NumberOfNewlyIssuedSharesPurchased" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="regn_GrossSalesRevenueMember" abstract="true" name="GrossSalesRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_GainContingencyClaimsInvalidatedNumber" abstract="false" name="GainContingencyClaimsInvalidatedNumber" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="regn_AggregatePaymentReceivedWithRegardsToAmendment" abstract="false" name="AggregatePaymentReceivedWithRegardsToAmendment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_PeriodForAchievingSalesTargetForMilestonePaymentRollingBasis" abstract="false" name="PeriodForAchievingSalesTargetForMilestonePaymentRollingBasis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="regn_AssetsAndLiabilitiesLesseeTableTextBlock" abstract="false" name="AssetsAndLiabilitiesLesseeTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="regn_PercentageOfTrialCostsRequiredToBeFundedByCollaboratingParty" abstract="false" name="PercentageOfTrialCostsRequiredToBeFundedByCollaboratingParty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_LineOfCreditFacilityIncreaseLimit" abstract="false" name="LineOfCreditFacilityIncreaseLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_AlnylamPharmaceuticalsInc.CollaborationAgreementMember" abstract="true" name="AlnylamPharmaceuticalsInc.CollaborationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_MaximumAmountOfSalesMilestonePaymentsIfTotalSalesAchieveSpecificLevels" abstract="false" name="MaximumAmountOfSalesMilestonePaymentsIfTotalSalesAchieveSpecificLevels" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_AmountsRecognizedInConnectionWithUpFrontPaymentsMember" abstract="true" name="AmountsRecognizedInConnectionWithUpFrontPaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_ReimbursementForManufacturingOfCommercialSuppliesMember" abstract="true" name="ReimbursementForManufacturingOfCommercialSuppliesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_AmendedRestatedLongTermIncentivePlan2014Member" abstract="true" name="AmendedRestatedLongTermIncentivePlan2014Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_Levelsoftwelvemonthsalesatwhichsalesmilestonepaymentswouldbereceived" abstract="false" name="Levelsoftwelvemonthsalesatwhichsalesmilestonepaymentswouldbereceived" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_EffectiveIncomeTaxRateReconciliationDeductionForeignIntangibleIncomePercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationDeductionForeignIntangibleIncomePercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_AmendedIODiscoveryAgreementMember" abstract="true" name="AmendedIODiscoveryAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_ResearchCollaborationAndLicensingArrangementsLineItems" abstract="true" name="ResearchCollaborationAndLicensingArrangementsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="regn_MarketableSecuritiesRealizedLoss" abstract="false" name="MarketableSecuritiesRealizedLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_AmendedIODiscoveryAgreementMUC16xCD3ProgramMember" abstract="true" name="AmendedIODiscoveryAgreementMUC16xCD3ProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_PraluentNetProductSalesMember" abstract="true" name="PraluentNetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_RemainingAmountOfSalesMilestonePaymentsIfTotalSalesAchieveSpecificLevels" abstract="false" name="RemainingAmountOfSalesMilestonePaymentsIfTotalSalesAchieveSpecificLevels" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_AmendedIODiscoveryAgreementBCMAxCD3ProgramMember" abstract="true" name="AmendedIODiscoveryAgreementBCMAxCD3ProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_ComputerEquipmentAndSoftwareMember" abstract="true" name="ComputerEquipmentAndSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_FinanceLeaseRemainingLeaseTerm" abstract="false" name="FinanceLeaseRemainingLeaseTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="regn_ShareOfLossesOutsideUnitedStatesForCollaboratingParty" abstract="false" name="ShareOfLossesOutsideUnitedStatesForCollaboratingParty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_PercentageOfQuarterlyProfitsRequiredToBePaidForReimbursementOfDevelopmentCosts" abstract="false" name="PercentageOfQuarterlyProfitsRequiredToBePaidForReimbursementOfDevelopmentCosts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="regn_ResearchAndDevelopmentArrangementContractToPerformForOthersByProductAxis" abstract="true" name="ResearchAndDevelopmentArrangementContractToPerformForOthersByProductAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_SanofiCollaborationAgreementImmunooncologyMember" abstract="true" name="SanofiCollaborationAgreementImmunooncologyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="regn_ReimbursementOfResearchAndDevelopmentExpensesMember" abstract="true" name="ReimbursementOfResearchAndDevelopmentExpensesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
</xs:schema>
