<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType><periodOfReport>2003-10-02</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000765880</issuerCik>
        <issuerName>HEALTH CARE PROPERTY INVESTORS INC</issuerName>
        <issuerTradingSymbol>HCP</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001234607</rptOwnerCik>
            <rptOwnerName>ELCAN CHARLES A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4675 MACARTHUR COURT</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEWPORT BEACH</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92660</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Executive Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>LLC Units (Right to Buy)</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F1"/></exerciseDate><expirationDate><footnoteId id="F1"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>610397.02</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">The units are redeemable at the election of the holder on or after October 1, 2004 and through September 30, 2012.  The units are redeemable at the election of Health Care Property Investors, Inc. (HCPI) on or after September 30, 2013.  The units are redeemable into shares of Common Stock or cash, at the discretion of HCPI.</footnote><footnote id="F2">1 for 1</footnote></footnotes><remarks/><ownerSignature><signatureName>Charles A. Elcan</signatureName><signatureDate>2003-10-06</signatureDate></ownerSignature></ownershipDocument>

