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

    <documentType>4</documentType><periodOfReport>2003-10-01</periodOfReport>
    <issuer>
        <issuerCik>0000740260</issuerCik>
        <issuerName>VENTAS INC</issuerName>
        <issuerTradingSymbol>VTR</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001198222</rptOwnerCik>
            <rptOwnerName>ROSENBERG SHELI  Z</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO NORTH RIVERSIDE PLAZA, SUITE 600</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>2003-10-01</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>419</value></transactionShares><transactionPricePerShare><value>17.90</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>27894.542</value><footnoteId id="F1"/><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><footnotes><footnote id="F1">As of October 1, 2003 Reporting Person also owns options to purchase 20,000 shares of the Issuer's common stock.</footnote><footnote id="F2">Includes 417.653 shares acquired on September 25, 2003 under the Ventas, Inc. Distribution Reinvestment and Stock Purchase Plan.</footnote></footnotes><remarks/><ownerSignature><signatureName>Sheli Z. Rosenberg, By: T. Richard Riney, Attorney-In-Fact</signatureName><signatureDate>2003-10-03</signatureDate></ownerSignature></ownershipDocument>
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X0201
4
2003-10-01
0000740260
VENTAS INC
VTR
0001198222
ROSENBERG SHELI  Z
TWO NORTH RIVERSIDE PLAZA, SUITE 600
CHICAGO
IL
60606
1
0
0
0
Common Stock
2003-10-01
4
A
0
419
17.90
A
27894.542
D
As of October 1, 2003 Reporting Person also owns options to purchase 20,000 shares of the Issuer's common stock.
Includes 417.653 shares acquired on September 25, 2003 under the Ventas, Inc. Distribution Reinvestment and Stock Purchase Plan.
Sheli Z. Rosenberg, By: T. Richard Riney, Attorney-In-Fact
2003-10-03