<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2007-04-25</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000856751</issuerCik>
        <issuerName>FIRST KEYSTONE FINANCIAL INC</issuerName>
        <issuerTradingSymbol>FKFS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001397156</rptOwnerCik>
            <rptOwnerName>VIDINLI NEDRET E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FIRST KEYSTONE FINANCIAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>22 WEST STATE STREET</rptOwnerStreet2>
            <rptOwnerCity>MEDIA</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19063</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>221515</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Fund (1)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares of common stock are owned by Financial Stocks Capital Partners IV, L.P. (&quot;FSCP&quot;).  Mr. Vidinli is an officer of Finstocks Capital Management IV, LLC, the general partner and portfolio manager of FSCP.  Mr. Vidinli has no dispositive or voting authority over said shares and disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein which, based on his investment in FSCP, amounts to less than 1% of the shares of common stock of First Keystone Financial, Inc. held by FSCP. This report shall not be deemed an admission that Mr. Vidinli is the beneficial owner of the disclaimed shares for purposes of Section 16 or otherwise.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Nedret Vidinli</signatureName>
        <signatureDate>2007-05-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
