-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 DU9YJXdbLBGe2nK6AuBhq9hg+JHPCkTQBBVEG6dKafscvzqj6Dsn5TqFmn+DFOeN
 tZoFC7534pSf7j3Xnnk8Pw==

<SEC-DOCUMENT>0000944695-03-000014.txt : 20030515
<SEC-HEADER>0000944695-03-000014.hdr.sgml : 20030515
<ACCEPTANCE-DATETIME>20030515121020
ACCESSION NUMBER:		0000944695-03-000014
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030514
FILED AS OF DATE:		20030515

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALLMERICA FINANCIAL CORP
		CENTRAL INDEX KEY:			0000944695
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				043263626
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		440 LINCOLN ST
		CITY:			WORCESTER
		STATE:			MA
		ZIP:			01653
		BUSINESS PHONE:		5088551000

	MAIL ADDRESS:	
		STREET 1:		440 LINCOLN ST
		CITY:			WORCESTER
		STATE:			MA
		ZIP:			01653

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HARRISON GAIL L
		CENTRAL INDEX KEY:			0001227466

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13754
		FILM NUMBER:		03702389

	BUSINESS ADDRESS:	
		STREET 1:		3601 N. JEFFERSON ST.
		CITY:			ARLINGTON
		STATE:			VA
		ZIP:			22207
		BUSINESS PHONE:		6172415855

	MAIL ADDRESS:	
		STREET 1:		3601 N. JEFFERSON ST.
		CITY:			ARLINGTON
		STATE:			VA
		ZIP:			22207
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-05-14</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000944695</issuerCik>
        <issuerName>ALLMERICA FINANCIAL CORP</issuerName>
        <issuerTradingSymbol>AFC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227466</rptOwnerCik>
            <rptOwnerName>HARRISON GAIL L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-05-14</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>A</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
            <footnoteId id="F1"/>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>1500</value>
            </transactionShares>
            <transactionValue>
                <value>0</value>
                <footnoteId id="F1"/>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>4168</value>
                <footnoteId id="F2"/>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">Shares granted as portion of annual retainer fee pursuant to Issuer's Amended and Restated Non-Employee Director Stock Ownership Plan.</footnote>
        <footnote id="F2">5,369 shares of Common Stock held indirectly by rabbi trust following reported transaction, pursuant to deferral agreement.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Charles F. Cronin, pursuant to Confirming Statement</signatureName>
        <signatureDate>2003-05-15</signatureDate>
    </ownerSignature>

</ownershipDocument>

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