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

    <documentType>4</documentType><periodOfReport>2003-11-24</periodOfReport>
    <issuer>
        <issuerCik>0000732713</issuerCik>
        <issuerName>BELLSOUTH CORP</issuerName>
        <issuerTradingSymbol>BLS</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001162744</rptOwnerCik>
            <rptOwnerName>FELDSTEIN KATHLEEN F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>147 CLIFTON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BELMONT</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02178</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Phantom Deferral Shares</value></securityTitle><conversionOrExercisePrice><footnoteId id="F1"/></conversionOrExercisePrice><transactionDate><value>2003-11-24</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F2"/></transactionCoding><transactionAmounts><transactionShares><value>128.9063</value></transactionShares><transactionPricePerShare><value>25.60</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2010-01-01</value></exerciseDate><expirationDate><value>2010-01-01</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>128.9063</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>14730.6009</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">SHARES OF PHANTOM STOCK CONVERT TO COMMON STOCK ON A ONE-FOR-ONE BASIS.</footnote><footnote id="F2">SHARES OF PHANTOM STOCK ACQUIRED PURSUANT TO BELLSOUTH CORPORATION DEFERRAL PLAN IN TRANSACTIONS EXEMPT UNDER RULE 16b-3(d).</footnote><footnote id="F3">INCLUDES SHARES OF PHANTOM STOCK ACQUIRED AS A RESULT OF REINVESTMENT OF DIVIDENDS ACCRUED ON PHANTOM SHARES PREVIOUSLY ACQUIRED UNDER VARIOUS DEFERRAL PLANS IN TRANSACTIONS EXEMPT UNDER RULE 16b-3 AND DEFERRED INTO PHANTOM ACCOUNT.</footnote></footnotes><remarks/><ownerSignature><signatureName>Marcy A. Bass, Attorney in Fact</signatureName><signatureDate>2003-11-25</signatureDate></ownerSignature></ownershipDocument>

