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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-09-25</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001127703</issuerCik>
        <issuerName>PROASSURANCE CORP</issuerName>
        <issuerTradingSymbol>PRA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194792</rptOwnerCik>
            <rptOwnerName>MORELLO JAMES J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PROASSURANCE CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>100 BROOKWOOD PLACE</rptOwnerStreet2>
            <rptOwnerCity>BIRMINGHAM</rptOwnerCity>
            <rptOwnerState>AL</rptOwnerState>
            <rptOwnerZipCode>35209-6811</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former Sec 16 Reporting Person</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <remarks>Mr. Morrello has ceased to be a Section 16 reporting person.</remarks>

    <ownerSignature>
        <signatureName>Frank B. O'Neil, POA for Jim Morello</signatureName>
        <signatureDate>2008-09-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
