-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000702325-10-000085.txt : 20100427
<SEC-HEADER>0000702325-10-000085.hdr.sgml : 20100427
<ACCEPTANCE-DATETIME>20100427180717
ACCESSION NUMBER:		0000702325-10-000085
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100423
FILED AS OF DATE:		20100427
DATE AS OF CHANGE:		20100427

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Carapella Victor P
		CENTRAL INDEX KEY:			0001452076

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10967
		FILM NUMBER:		10774637

	MAIL ADDRESS:	
		STREET 1:		ONE PIERCE PLACE
		STREET 2:		SUITE 1500
		CITY:			ITASCA
		STATE:			X1
		ZIP:			60143

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST MIDWEST BANCORP INC
		CENTRAL INDEX KEY:			0000702325
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		IRS NUMBER:				363161078
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE PIERCE PLACE
		STREET 2:		SUITE 1500
		CITY:			ITASCA
		STATE:			IL
		ZIP:			60143
		BUSINESS PHONE:		6308757450

	MAIL ADDRESS:	
		STREET 1:		ONE PIERCE PLACE
		STREET 2:		SUITE 1500
		CITY:			ITASCA
		STATE:			IL
		ZIP:			60143
</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>2010-04-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000702325</issuerCik>
        <issuerName>FIRST MIDWEST BANCORP INC</issuerName>
        <issuerTradingSymbol>FMBI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001452076</rptOwnerCik>
            <rptOwnerName>Carapella Victor P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE PIERCE PLACE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1500</rptOwnerStreet2>
            <rptOwnerCity>ITASCA</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60143</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Comm'l Banking Group Mgr.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-04-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>106</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>46495</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48915</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By NQ Stock Option Gain Deferral Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25597</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Profit Sharing Plan Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents a portion of base salary paid to the Reporting Person in bi-weekly installments of fully vested shares. The Reporting Person may not transfer the shares during the period the Company has any obligations outstanding under the U.S. Treasury's Troubled Asset Relief Program except in the case of the Reporting Person's death or disability.</footnote>
        <footnote id="F2">The number of shares represented by this award was determined by dividing the dollar value of the award granted to the Reporting Person by $16.545 (the average high and low sale price of one share of the company's common stock as quoted on the Nasdaq Stock Market on April 22, 2010).</footnote>
        <footnote id="F3">Between April 13, 2010 and April 27, 2010 the Reporting Person acquired 6 shares of First Midwest Bancorp, Inc. Common Stock under the First Midwest Bancorp, Inc. Dividend Reinvestment Plan.  The aggregate information reported in this line item includes such shares as reported in a plan statement dated April 13, 2010.</footnote>
        <footnote id="F4">Between January 20, 2010 and April 27, 2010 the Reporting Person acquired 34 shares of First Midwest Bancorp, Inc. Common Stock under the First Midwest Bancorp, Inc. Non-Qualified Gain Deferral Plan pursuant to the Dividend Reinvestment feature of the Plan.  This information is based on a plan statement dated April 13, 2010.</footnote>
        <footnote id="F5">Between January 20, 2010 and April 27, 2010 the Reporting Person acquired 17 shares of First Midwest Bancorp, Inc. Common Stock under the First Midwest Bancorp, Inc. Savings and Profit Sharing Plan.  The information in this report is based on a plan statement dated April 20, 2010.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Andrea L. Stangl, Attorney-in-fact for Victor P. Carapella</signatureName>
        <signatureDate>2010-04-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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