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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 RV5/SNafMEGNfF7Wtm7De5Cr8l/tOAbzyfhfcEndqOUhG6ao8TLfRFAaCZ4YBryc
 ZISi970aIO33/gSjfsX3nA==

<SEC-DOCUMENT>0001042046-03-000228.txt : 20031211
<SEC-HEADER>0001042046-03-000228.hdr.sgml : 20031211
<ACCEPTANCE-DATETIME>20031211100555
ACCESSION NUMBER:		0001042046-03-000228
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031210
FILED AS OF DATE:		20031211

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MARTIN WILLIAM R
		CENTRAL INDEX KEY:			0001185856

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13653
		FILM NUMBER:		031048583

	BUSINESS ADDRESS:	
		STREET 1:		ONE EAST FOURTH STREET
		STREET 2:		SUITE 919
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45202
		BUSINESS PHONE:		5135792540

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMERICAN FINANCIAL GROUP INC
		CENTRAL INDEX KEY:			0001042046
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				311544320
		STATE OF INCORPORATION:			OH
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE EAST FOURTH STREET
		STREET 2:		SUITE 919
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45202
		BUSINESS PHONE:		5135792121

	MAIL ADDRESS:	
		STREET 1:		ONE EAST FOURTH STREET
		STREET 2:		SUITE 919
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45202

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AMERICAN FINANCIAL GROUP HOLDINGS INC
		DATE OF NAME CHANGE:	19970709
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-12-10</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001042046</issuerCik>
        <issuerName>AMERICAN FINANCIAL GROUP INC</issuerName>
        <issuerTradingSymbol>AFG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001185856</rptOwnerCik>
            <rptOwnerName>MARTIN WILLIAM R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE EAST FOURTH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CINCINNATI</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>45202</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>2003-12-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2400</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>75258</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12297</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>#1</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares were a gift.</footnote>
        <footnote id="F2">Indirect #1:  These shares are held by the Reporting Person's spouse.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Karl J. Grafe, as Attorney-in-Fact for William R. Martin</signatureName>
        <signatureDate>2003-12-11</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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