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

    <documentType>4</documentType><periodOfReport>2003-12-31</periodOfReport>
    <issuer>
        <issuerCik>0000004904</issuerCik>
        <issuerName>AMERICAN ELECTRIC POWER CO INC</issuerName>
        <issuerTradingSymbol>AEP</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001186288</rptOwnerCik>
            <rptOwnerName>SANDOR RICHARD L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1 RIVERSIDE PLAZA, 29TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>COLUMBUS</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>43215</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Phantom Stock Unit</value><footnoteId id="F1"/></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F2"/></conversionOrExercisePrice><transactionDate><value>2003-12-31</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>245</value></transactionShares><transactionPricePerShare><value>0</value><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>245</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6011</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Phantom Stock Unit</value><footnoteId id="F4"/></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F5"/></conversionOrExercisePrice><transactionDate><value>2003-12-31</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>491</value></transactionShares><transactionPricePerShare><value>0</value><footnoteId id="F5"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F5"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>491</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6558</value><footnoteId id="F6"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Acquisition pursuant to the AEP Deferred Compensation and Stock Plan for Non-Employee Directors.</footnote><footnote id="F2">Deferred Units are payable in cash  upon termination of service unless the director has elected to defer payment for a period that results in payment commencing not later than five years thereafter.</footnote><footnote id="F3">Includes 17 units of reinvested dividends for 4th Quarter, 2003 pursuant to a dividend reinvestment feature of the Plan.</footnote><footnote id="F4">Acquisition pursuant to the AEP Stock Unit Accumulation Plan for Non-Employee Directors.</footnote><footnote id="F5">Stock Units are paid to the director in cash upon termination of service unless the director has elected to defer payment for a period that results in payment commencing not later than five years thereafter.</footnote><footnote id="F6">Includes 55 units of reinvested dividends for 4th Quarter, 2003 pursuant to a dividend reinvestment feature of the Plan.</footnote></footnotes><remarks/><ownerSignature><signatureName>Kevin R. Fease, Attorney-in-Fact for Richard L. Sandor</signatureName><signatureDate>2004-01-05</signatureDate></ownerSignature></ownershipDocument>

