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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000702325-10-000072.txt : 20100329
<SEC-HEADER>0000702325-10-000072.hdr.sgml : 20100329
<ACCEPTANCE-DATETIME>20100329132248
ACCESSION NUMBER:		0000702325-10-000072
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100326
FILED AS OF DATE:		20100329
DATE AS OF CHANGE:		20100329

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCUDDER MICHAEL L
		CENTRAL INDEX KEY:			0001199246

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10967
		FILM NUMBER:		10710050

	MAIL ADDRESS:	
		STREET 1:		300 PARK BLVD
		STREET 2:		SUITE 405
		CITY:			ITASCA
		STATE:			IL
		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>2010-03-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001199246</rptOwnerCik>
            <rptOwnerName>SCUDDER MICHAEL L</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>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-03-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>585</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>131728</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8888</value>
                </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>6230</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Profit Sharing Plan Trust</value>
                    <footnoteId id="F3"/>
                </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 $14.1550 (the average high and low sale price of one share of the Company's common stock as quoted on the Nasdaq Stock Market on March 25, 2010).</footnote>
        <footnote id="F3">Between March 17, 2010 and March 29, 2010 the Reporting Person acquired 35 shares of First Midwest Bancorp, Inc. Common Stock under the First Midwest Bancorp, Inc. Savings and Profit Sharing Plan pursuant to payroll contributions.  This information is based on a plan statement dated March 18, 2010.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Jessica L. Friedman Attorney-in-fact for Michael L. Scudder</signatureName>
        <signatureDate>2010-03-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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