Exhibit 99.1



The  following  certification  is provided by the  undersigned  Chief  Executive
Officer and Chief  Financial  Officer of Wintrust  Financial  Corporation on the
basis of such  officers'  knowledge and belief for the sole purpose of complying
with  18  U.S.C.  Section  1350,  as  adopted  pursuant  to  Section  906 of the
Sarbanes-Oxley Act of 2002.

                                  CERTIFICATION


In  connection  with the Annual  Report of the  Wintrust  Financial  Corporation
Retirement  Savings  Plan (the  "Plan") on Form 11-K for the  fiscal  year ended
December 31, 2002, as filed with the Securities and Exchange  Commission on June
24, 2003, (the "Report"), the undersigned hereby certify,  pursuant to 18 U.S.C.
Section 1350, as adopted  pursuant to Section 906 of the  Sarbanes-Oxley  Act of
2002, that:

      (1)   The Report fully complies with the  requirements of Section 13(a) or
            15(d) of the Securities Exchange Act of 1934, as amended; and

      (2)   The  information  contained in the Report  fairly  presents,  in all
            material respects, the financial condition and results of operations
            of the Plan.


                                   /s/  EDWARD J. WEHMER
                                   ---------------------------------------------
                                    Name:  Edward J. Wehmer
                                   Title:  President and Chief Executive Officer
                                    Date:  June 24, 2003




                                   /s/  DAVID L. STOEHR
                                   ---------------------------------------------
                                    Name:  David L. Stoehr
                                   Title:  Executive Vice President and
                                           Chief Financial Officer
                                    Date:  June 24, 2003



A signed  original of this  written  statement  required by Section 906 has been
provided to the Company and will be retained by the Company and furnished to the
Securities and Exchange Commission upon request. This certification  accompanies
the Report and shall not be treated as having been filed as part of this Report.