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

    <documentType>4</documentType><periodOfReport>2003-12-16</periodOfReport>
    <issuer>
        <issuerCik>0000740260</issuerCik>
        <issuerName>VENTAS INC</issuerName>
        <issuerTradingSymbol>VTR</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001195500</rptOwnerCik>
            <rptOwnerName>CROCKER DOUGLASS II</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO NORTH RIVERSIDE PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-16</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>48</value></transactionShares><transactionPricePerShare><value>21.00</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>36136</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><footnotes><footnote id="F1">As of December 16, 2003, Reporting Person also owns options to purchase 235,000 shares of Issuer's common stock.</footnote></footnotes><remarks/><ownerSignature><signatureName>Douglas Crocker, II By: T. Richard Riney, Attorney-In-Fact</signatureName><signatureDate>2003-12-17</signatureDate></ownerSignature></ownershipDocument>
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X0201
4
2003-12-16
0000740260
VENTAS INC
VTR
0001195500
CROCKER DOUGLASS II
TWO NORTH RIVERSIDE PLAZA
CHICAGO
IL
60606
1
0
0
0
Common Stock
2003-12-16
4
A
0
48
21.00
A
36136
D
As of December 16, 2003, Reporting Person also owns options to purchase 235,000 shares of Issuer's common stock.
Douglas Crocker, II By: T. Richard Riney, Attorney-In-Fact
2003-12-17