-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Vd83jTlfJJY84+qSzsb2Fewbg8/JnSTx6y9xMY1mW1CFRg/vEmb0ed971rRT0Lfj
 EX7Iz4TRCgqaCNqqUDvYaw==

<SEC-DOCUMENT>0000702325-09-000114.txt : 20091208
<SEC-HEADER>0000702325-09-000114.hdr.sgml : 20091208
<ACCEPTANCE-DATETIME>20091208180842
ACCESSION NUMBER:		0000702325-09-000114
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091204
FILED AS OF DATE:		20091208
DATE AS OF CHANGE:		20091208

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kullander David D
		CENTRAL INDEX KEY:			0001464492

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10967
		FILM NUMBER:		091229639

	MAIL ADDRESS:	
		STREET 1:		ONE PIERCE PLACE
		STREET 2:		SUITE 1500
		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>2009-12-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001464492</rptOwnerCik>
            <rptOwnerName>Kullander David D</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, Bank Operations Director</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock under NQ Retirement Plan</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-12-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>76</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.8718</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>76</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1136</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares of phantom stock acquired under the Nonqualified Retirement Plan have a 1-for-1 conversion ratio and are payable in cash upon distribution to the Participant in accordance with the terms of the Plan.</footnote>
        <footnote id="F2">Between November 25, 2009 and December 8, 2009 the Reporting Person acquired 76 shares of First Midwest Bancorp, Inc. Common Stock under the First Midwest Bancorp, Inc. Nonqualified Retirement Plan through the bi-weekly employee contribution feature of the Plan.  The information in this report is based on a plan statement dated December 4, 2009.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Andrea L. Stangl, Attorney-in-fact for          David D. Kullander</signatureName>
        <signatureDate>2009-12-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----