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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 T3IMLA4YGMw04qz1A6yb1vltPN9Rc/dyJvvOdLWhawV1Fwk4Qky8YAs0XvXOh3eg
 b/eN4bXWegbkguvpenX6Qw==

<SEC-DOCUMENT>0000913849-06-000022.txt : 20060104
<SEC-HEADER>0000913849-06-000022.hdr.sgml : 20060104
<ACCEPTANCE-DATETIME>20060104155112
ACCESSION NUMBER:		0000913849-06-000022
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051231
FILED AS OF DATE:		20060104
DATE AS OF CHANGE:		20060104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			REYES J CHRISTOPHER
		CENTRAL INDEX KEY:			0001111733

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21923
		FILM NUMBER:		06507495

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		8472335459

	MAIL ADDRESS:	
		STREET 1:		3600 NORTH RIVER RD
		CITY:			FRANKLIN PK
		STATE:			IL
		ZIP:			60131

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			WINTRUST FINANCIAL CORP
		CENTRAL INDEX KEY:			0001015328
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				363873352
		STATE OF INCORPORATION:			IL
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		727 N BANK LANE
		CITY:			LAKE FOREST
		STATE:			IL
		ZIP:			60045
		BUSINESS PHONE:		8476154096

	MAIL ADDRESS:	
		STREET 1:		727 N BANK LN
		CITY:			LAKE FOREST
		STATE:			IL
		ZIP:			60045
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001015328</issuerCik>
        <issuerName>WINTRUST FINANCIAL CORP</issuerName>
        <issuerTradingSymbol>WTFC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001111733</rptOwnerCik>
            <rptOwnerName>REYES J CHRISTOPHER</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>9500 WEST BRYN MAWR AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 700</rptOwnerStreet2>
            <rptOwnerCity>ROSEMONT</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60018</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>2005-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>513</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>50.575</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>217829</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25375</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse as Trustee</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares earned for the fourth quarter of 2005 for services as a Director of the Company in accordance with the Directors Deferred Fee and Stock Plan approved by the Shareholders.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David A. Dykstra, Attorney-in-Fact</signatureName>
        <signatureDate>2006-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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