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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 T3bDHc5iEIIaSYHMJVkrmrd4cE/p8M9sCnIBs/euAoYIWGH0KfR41xhgqDE1l7z4
 gbkIzR/F+jUNSDUuwEoZAw==

<SEC-DOCUMENT>0001245557-10-000001.txt : 20100528
<SEC-HEADER>0001245557-10-000001.hdr.sgml : 20100528
<ACCEPTANCE-DATETIME>20100528132757
ACCESSION NUMBER:		0001245557-10-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100527
FILED AS OF DATE:		20100528
DATE AS OF CHANGE:		20100528

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BARR RICHARD I
		CENTRAL INDEX KEY:			0001245557

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-04605
		FILM NUMBER:		10865652

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST OPPORTUNITY FUND INC
		CENTRAL INDEX KEY:			0000790202
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				133341573
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		2344 SPRUCE STREET
		STREET 2:		SUITE A
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302
		BUSINESS PHONE:		3034445483

	MAIL ADDRESS:	
		STREET 1:		2344 SPRUCE STREET
		STREET 2:		SUITE A
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST FINANCIAL FUND INC
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST SAVINGS & BANKING INSTITUTIONS FUND INC
		DATE OF NAME CHANGE:	19860402
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-05-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000790202</issuerCik>
        <issuerName>FIRST OPPORTUNITY FUND INC</issuerName>
        <issuerTradingSymbol>FOFI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001245557</rptOwnerCik>
            <rptOwnerName>BARR RICHARD I</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></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>2010-05-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.1</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11635</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Richard I. Barr</signatureName>
        <signatureDate>2010-05-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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