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 October 26, 2004 Wintrust Financial Corporation 727 North Bank Lane Lake Forest, Illinois 60045 Ladies and Gentlemen: Reference is hereby made to the Registration Statement on Form S-8 (the "Registration Statement") being filed with the Securities and Exchange Commission by Wintrust Financial Corporation, an Illinois corporation (the "Company"), relating to the registration of 94,177 shares of the Company's common stock, no par value per share (the "Common Stock"), that may be issued upon exercise of options previously granted by Town Bankshares, Ltd., a Wisconsin corporation ("Town Bankshares"), to employees or directors pursuant to the Town Bankshares, Ltd. 1997 Stock Incentive Plan, as amended (the "Town Bankshares Plan"). Town Bankshares was merged with and into the Company, effective October 15, 2004. We have acted as counsel for the Company in connection with this Registration Statement. In connection with our opinion, we have examined originals, or copies certified or otherwise identified to our satisfaction, of (i) the Registration Statement, (ii) the Amended and Restated Articles of Incorporation of the Company, (iii) the Amended and Restated Bylaws of the Company, and (iv) such other corporate records, documents and other papers as we deemed necessary to examine for purposes of this opinion. We have assumed the authenticity, accuracy and completeness of all documents submitted to us as originals, the conformity to authentic original documents of all documents submitted to us as certified, conformed or photostatic copies and the genuineness of all signatures. Based upon the foregoing and the number of shares of Common Stock issued and outstanding as of the date hereof, it is our opinion that the 94,177 shares of Common Stock of the Company, when issued in accordance with the terms of the Town Bankshares Plan, will be validly issued, fully paid and nonassessable. The opinion expressed herein is based on the facts in existence and the laws in effect on the date hereof and is limited to the Federal securities laws and the laws of the State of Illinois currently in effect. We hereby consent to the use of this opinion in connection with said Registration Statement and to the references to our firm therein. Very truly yours, /s/ VEDDER, PRICE, KAUFMAN & KAMMHOLZ, P.C.