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

    <documentType>4</documentType><periodOfReport>2004-01-05</periodOfReport>
    <issuer>
        <issuerCik>0000740260</issuerCik>
        <issuerName>VENTAS INC</issuerName>
        <issuerTradingSymbol>VTR</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001213928</rptOwnerCik>
            <rptOwnerName>GELLERT JAY M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>21650 OXNARD ST., 22ND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WOODLAND HILLS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>91367</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>22.15</value></conversionOrExercisePrice><transactionDate><value>2004-01-05</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>5000</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><value>22.15</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-01-05</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>2014-01-05</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value><footnoteId id="F3"/><footnoteId id="F4"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Options granted pursuant to the Ventas, Inc. 2000 Stock Option Plan for Directors.</footnote><footnote id="F2">The options are exercisable in cumulative 50% annual installments beginning on 1/5/04.</footnote><footnote id="F3">Represents the total number of unexercised stock options held by Mr. Gellert as of January 5, 2004.</footnote><footnote id="F4">As of January 5, 2004, Reporting Person also owns 8,867.829 shares of Issuer's common stock.</footnote></footnotes><remarks/><ownerSignature><signatureName>Jay M. Gellert, By: T. Richard Riney, Attorney-In-Fact</signatureName><signatureDate>2004-01-07</signatureDate></ownerSignature></ownershipDocument>
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X0201
4
2004-01-05
0000740260
VENTAS INC
VTR
0001213928
GELLERT JAY M
21650 OXNARD ST., 22ND FLOOR
WOODLAND HILLS
CA
91367
1
0
0
0
Stock Option (Right to Buy)
22.15
2004-01-05
4
A
0
5000
22.15
A
2004-01-05
2014-01-05
Common Stock
5000
25000
D
Options granted pursuant to the Ventas, Inc. 2000 Stock Option Plan for Directors.
The options are exercisable in cumulative 50% annual installments beginning on 1/5/04.
Represents the total number of unexercised stock options held by Mr. Gellert as of January 5, 2004.
As of January 5, 2004, Reporting Person also owns 8,867.829 shares of Issuer's common stock.
Jay M. Gellert, By: T. Richard Riney, Attorney-In-Fact
2004-01-07