-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
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 TYvgUZhHwN7UOaTvuJ/NoQ==

<SEC-DOCUMENT>0001179110-10-004704.txt : 20100308
<SEC-HEADER>0001179110-10-004704.hdr.sgml : 20100308
<ACCEPTANCE-DATETIME>20100308170749
ACCESSION NUMBER:		0001179110-10-004704
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100304
FILED AS OF DATE:		20100308
DATE AS OF CHANGE:		20100308

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MARAZZA JOHN A
		CENTRAL INDEX KEY:			0001285566

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33077
		FILM NUMBER:		10664463

	MAIL ADDRESS:	
		STREET 1:		465 CLEVELAND AVE
		CITY:			WATERVILLE
		STATE:			OH
		ZIP:			43082

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST MERCURY FINANCIAL CORP
		CENTRAL INDEX KEY:			0000929186
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				383164336
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		29621 NORTHWESTERN HWY
		STREET 2:		PO BOX 5096
		CITY:			SOUTHFIELD
		STATE:			MI
		ZIP:			48034
		BUSINESS PHONE:		8103584010

	MAIL ADDRESS:	
		STREET 1:		29621 NORTHWESTERN HGWY
		STREET 2:		PO BOX 5096
		CITY:			SOUTHFIELD
		STATE:			MI
		ZIP:			48086
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-03-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000929186</issuerCik>
        <issuerName>FIRST MERCURY FINANCIAL CORP</issuerName>
        <issuerTradingSymbol>FMR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001285566</rptOwnerCik>
            <rptOwnerName>MARAZZA JOHN A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>29110 INKSTER ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SOUTHFIELD</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>48034</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Exec. V.P.; CFO; Secretary</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-03-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>140600</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Transaction represents the grant of restricted stock to the reporting person under the Company's Omnibus Plan. The shares vest in three equal annual installments commencing on the first anniversary of the grant date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John A. Marazza</signatureName>
        <signatureDate>2010-03-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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