SECURITIES AND EXCHANGE COMMISSION

                              WASHINGTON, D.C. 20549

                             ------------------------

                                     FORM 8-K


                                  CURRENT REPORT


                      PURSUANT TO SECTION 13 OR 15(d) OF THE


                    SECURITIES EXCHANGE ACT OF 1934, AS AMENDED


         Date of Report (Date of earliest event reported): April 25, 1997


                        MERCANTILE BANCORPORATION INC.    
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              (Exact name of registrant as specified in its charter)




                Missouri                  1-11792         43-0951744            
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         (State of Incorporation)      (Commission       (IRS Employer
                                       File Number)   Identification No.) 





                  P.O. Box 524, St. Louis, Missouri              63166-0524
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         (Address of principal executive offices)                (Zip Code) 



                                  (314) 425-2525                           
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                  (Registrant's telephone number, including area code) 





                     INFORMATION TO BE INCLUDED IN THE REPORT

         ITEM 2.   ACQUISITION OR DISPOSITION OF ASSETS

                   At a special meeting of shareholders held on April 22,
         1997, the shareholders of Mark Twain Bancshares, Inc.
         ("Bancshares"), and at the Annual Meeting of Shareholders held on
         April 24, 1997, the shareholders of Mercantile Bancorporation Inc.
         ("MBI"), each voted upon and approved and adopted an Agreement and
         Plan of Reorganization, dated October 27, 1997, as amended (the
         "Merger Agreement"), by and between MBI, Ameribanc, Inc., a wholly
         owned subsidiary of MBI ("Merger Sub"), and Bancshares.  Pursuant
         to the Merger Agreement, Bancshares was merged (the "Merger") with
         and into Merger Sub, and, among other things, each share of
         Bancshares common stock, par value $1.25 per share ("Bancshares
         Common Stock"), other than shares held by Bancshares, MBI or any
         of their respective wholly owned subsidiaries, in each case other
         than in a fiduciary capacity or as a result of debts previously
         contracted, all of which were cancelled in the Merger, and other
         than shares held by shareholders of Bancshares who exercised their
         dissenters' rights under the Missouri General and Business
         Corporation Law, was converted into the right to receive .952 of a
         share of MBI common stock, par value $0.01 per share ("MBI Common
         Stock"), with cash in lieu of fractional shares.  It is
         anticipated that approximately 17,213,114 shares of MBI Common
         Stock will be issued pursuant to the Merger to former shareholders
         of Bancshares, inclusive of shares issuable upon exercise of
         options to purchase shares of MBI Common Stock into which
         outstanding options to purchase Bancshares Common Stock were
         converted in the Merger.  The Merger became effective as of April
         25, 1997.  As a result of the Merger, the business and operations
         of Bancshares will be continued through Merger Sub.

                   Bancshares was organized in 1967 and was a registered
         bank holding company under the federal Bank Holding Company Act of
         1956, as amended.  Bancshares operated 24 separate banking
         locations in the metropolitan St. Louis area (including four in
         Illinois) through two banking subsidiaries, Mark Twain Bank and
         Mark Twain Illinois Bank.  Bancshares also operated 15 separate
         locations in the metropolitan Kansas City bi-state area through
         another banking subsidiary, Mark Twain Kansas City Bank, and 3
         separate locations in the metropolitan Springfield, Missouri area
         through another banking subsidiary, First City National Bank.
         Bancshares subsidiaries also provided a variety of fixed income
         investment products, complete brokerage services and a complete
         line of personal trust, employee benefit plan, investment advisory
         and management, and corporate trust services.





                   MBI's Registration Statement on Form S-4 (Registration
         No. 333-23607), which was declared effective by the Securities and
         Exchange Commission on March 20, 1997, sets forth certain
         information regarding the Merger, MBI and Bancshares, including,
         without limitation, the effective time and manner of the Merger, a
         description of the assets involved, the nature and amount of
         consideration paid by MBI therefor, the method used for
         determining the amount of such consideration, the nature of any
         material relationships between Bancshares and MBI or any of its
         affiliates, any officer or director of MBI, or any associate of
         any such officer or director, the nature of Bancshares' business
         and MBI's intended use of the assets acquired in the Merger.






                                    Signatures
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         Pursuant to the requirements of the Securities Exchange Act of
         1934, as amended, the Registrant has duly caused this report to be
         signed on its behalf by the undersigned hereunto duly authorized. 




                                            MERCANTILE BANCORPORATION INC.
                                            (Registrant)



                                            By:  /s/ Jon W. Bilstrom
                                                 -----------------------
                                                 Name:  Jon W. Bilstrom
                                                 Title:  General Counsel
                                                         and Secretary




         Dated: May 2, 1997