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

    <documentType>4</documentType><periodOfReport>2003-11-13</periodOfReport>
    <issuer>
        <issuerCik>0000049071</issuerCik>
        <issuerName>HUMANA INC</issuerName>
        <issuerTradingSymbol>HUM</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001018652</rptOwnerCik>
            <rptOwnerName>REYNOLDS W ANN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 W. MAIN ST.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LOUISVILLE, KY</rptOwnerCity>
            <rptOwnerState>KY</rptOwnerState>
            <rptOwnerZipCode>40202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Humana Common</value><footnoteId id="F1"/></securityTitle><transactionDate><value>2003-11-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>5000</value></transactionShares><transactionPricePerShare><value>17.625</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>21435</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Humana Common</value><footnoteId id="F1"/></securityTitle><transactionDate><value>2003-11-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>5000</value></transactionShares><transactionPricePerShare><value>21.00</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>16435</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Humana Common</value><footnoteId id="F1"/></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>87</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F2"/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>17.625</value></conversionOrExercisePrice><transactionDate><value>2003-11-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>5000</value></transactionShares><transactionPricePerShare><value>17.625</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1995-01-03</value></exerciseDate><expirationDate><value>2004-01-03</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>22.4375</value></conversionOrExercisePrice><exerciseDate><value>1996-01-03</value></exerciseDate><expirationDate><value>2005-01-03</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>26.9375</value></conversionOrExercisePrice><exerciseDate><value>1997-01-02</value></exerciseDate><expirationDate><value>2006-01-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>18.9375</value></conversionOrExercisePrice><exerciseDate><value>1998-01-02</value></exerciseDate><expirationDate><value>2007-01-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>21.25</value></conversionOrExercisePrice><exerciseDate><value>1999-01-02</value></exerciseDate><expirationDate><value>2008-01-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>18.7813</value></conversionOrExercisePrice><exerciseDate><value>2000-01-04</value></exerciseDate><expirationDate><value>2009-01-04</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>7.875</value></conversionOrExercisePrice><exerciseDate><value>2001-01-03</value></exerciseDate><expirationDate><value>2010-01-03</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F4"/></securityTitle><conversionOrExercisePrice><value>14.7813</value></conversionOrExercisePrice><exerciseDate><value>2002-01-02</value></exerciseDate><expirationDate><value>2011-01-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F4"/></securityTitle><conversionOrExercisePrice><value>11.55</value></conversionOrExercisePrice><exerciseDate><value>2003-01-02</value></exerciseDate><expirationDate><value>2012-01-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options</value><footnoteId id="F4"/></securityTitle><conversionOrExercisePrice><value>10.19</value></conversionOrExercisePrice><exerciseDate><value>2004-01-02</value></exerciseDate><expirationDate><value>2013-01-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Humana Common</value><footnoteId id="F1"/></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Each share of Common Stock contains a Right adopted on March 5, 1987, pursuant to the Company Rights Agreement, as amended and restated on February 14, 1996, and amended as of May 27, 1998 and March 1, 1999, which entitles holders of the Company's Common Stock, in the  event certain specified events occur, to acquire 1/100 of a share of Series A Participating Preferred Stock at a price of $145 per fractional share.</footnote><footnote id="F2">Shares held by reporting person's spouse.</footnote><footnote id="F3">Right to buy pursuant to Humana Inc.'s 1989 Stock Option Plan for Non-Employee Directors.</footnote><footnote id="F4">Right to buy pursuant to Humana Inc.'s 1996 Incentive Stock Option Plan.</footnote></footnotes><remarks/><ownerSignature><signatureName>W. Ann Reynolds, Ph.D.</signatureName><signatureDate>2003-11-13</signatureDate></ownerSignature></ownershipDocument>

