EXHIBIT 5.1 VEDDER PRICE VEDDER, PRICE, KAUFMAN & KAMMHOLZ, P.C. 222 NORTH LASALLE STREET CHICAGO, ILLINOIS 60601-1003 312-609-7500 FACSIMILE: 312-609-5005 OFFICES IN CHICAGO, NEW YORK CITY AND LIVINGSTON, NEW JERSEY August 20, 2004 Wintrust Financial Corporation 727 North Bank Lane Lake Forest, IL 60045 Ladies and Gentlemen: Reference is hereby made to the Form S-4 Registration Statement (the "Registration Statement") being filed by Wintrust Financial Corporation, an Illinois corporation ("Wintrust"), relating to the registration of up to 583,000 shares of Wintrust common stock, no par value, that may be issued to shareholders of Town Bankshares, Ltd., a Wisconsin corporation ("Town Bankshares"). Such shares are to be issued in exchange for shares of Town Bankshares common stock, par value $0.01 per share, pursuant to the proposed merger (the "Merger") of Town Bankshares with Wintrust in accordance with the terms and conditions of that certain Agreement and Plan of Merger dated as of June 14, 2004 by and between Wintrust and Town Bankshares (the "Merger Agreement"). In rendering this opinion, we have examined such documents and materials, including the Amended and Restated Articles of Incorporation and the Amended and Restated By-laws of Wintrust, and other corporate documents and records of Wintrust, as we have deemed necessary for the purpose of providing this opinion. On the basis of the foregoing, it is our opinion that such shares of Wintrust common stock, if and when issued to Town Bankshares shareholders in accordance with and pursuant to the Merger Agreement, will be validly issued, fully paid and nonassessable. We hereby consent to the filing of this opinion as part of the Registration Statement and to the reference of our name under the heading "Legal Matters" in the proxy statement/prospectus included therein. Very truly yours, /s/ VEDDER, PRICE, KAUFMAN & KAMMHOLZ, P.C.