8-K

                       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
                                  July 1, 1998
                Date of Report (Date of Earliest Event Reported)
                         MERCANTILE BANCORPORATION INC.
             (Exact Name of Registrant as Specified in its Charter)
                                    Missouri
                 (State or Other Jurisdiction of Incorporation)

                   1-11792                           43-0951744
           (Commission File Number)      (IRS Employer Identification No.)

                  P.O. Box 524
                  St. Louis, Missouri                             63166-0524
                  (Address of Principal Executive Offices)        (Zip Code)

                  (314) 425-2525
                  (Registrant's Telephone Number, including Area Code)






ITEM 5.     OTHER EVENTS

      At its annual meeting of stockholders held on June 29, 1998, the
stockholders of Firstbank of Illinois Co., a Delaware corporation ("Firstbank"),
voted to approve and adopt an Agreement and Plan of Reorganization, dated
January 30, 1998, between Mercantile Bancorporation Inc. ("MBI"), a Missouri
corporation, Ameribanc, Inc., a Delaware corporation and wholly-owned subsidiary
of MBI ("Ameribanc"), and Firstbank (the "Merger Agreement"). Pursuant to the
Merger Agreement, Firstbank merged (the "Merger") with and into Ameribanc
effective July 1, 1998. Pursuant to the Merger Agreement, each share of common
stock, par value $1.00 per share, of Firstbank ("Firstbank Common Stock") was
converted into the right to receive 0.8308 shares of common stock, par value
$0.01 per share, of MBI ("MBI Common Stock"), with cash distributed in lieu of
fractional shares, other than shares held by Firstbank, MBI or any of their
respective subsidiaries (other than in a fiduciary capacity or as a result of
debts previously contracted), which were cancelled. An aggregate of
approximately 13,786,135 shares of MBI Common Stock will be issued in the Merger
to former shareholders of Firstbank, inclusive of shares issuable upon exercise
of options to purchase shares of MBI Common Stock into which outstanding options
to purchase Firstbank Common Stock were converted in the Merger.

      The Merger was accounted for as a "pooling of interests" for accounting
and financial reporting purposes. Under this method of accounting, the recorded
assets, liabilities, stockholders' equity, income and expenses of MBI and
Firstbank have been combined and reflected at their historical amounts. MBI's
Registration Statement on Form S-4 (Registration No. 333-51329) sets forth
certain additional information regarding the Merger, MBI and Firstbank.

      A copy of the press release issued by MBI announcing the closing of the
Merger is attached hereto as Exhibit 99.1.

ITEM 7.     FINANCIAL STATEMENTS AND EXHIBITS

(a)   Financial statements of businesses acquired.

      Not applicable.

(b)   Pro forma financial information.

      Not applicable.

(c)   Exhibits.

      99.1  Press release






                                    SIGNATURE

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunder duly authorized.

Dated:  July 16, 1998

                                    MERCANTILE BANCORPORATION INC.

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






EXHIBIT INDEX

99.1       Press release.

EX-99

                                                                    Exhibit 99.1

MERCANTILE BANCORPORATION INC. COMPLETES
MERGER WITH FIRSTBANK OF ILLINOIS CO.

PR Newswire - July 01, 1998 17:32

ST. LOUIS, July 1 /PRNewswire/ -- MERCANTILE BANCORPORATION INC. (NYSE: MTL),
the St. Louis-based bank holding company, announced today the completion of its
merger with Firstbank of Illinois Co., headquartered in Springfield, Illinois.
Firstbank of Illinois Co. is a $2.2 billion multi-bank holding company which
operates offices across 11 banking markets in Illinois. The merger with
Firstbank will significantly strengthen Mercantile's presence in Illinois,
moving the bank from the third to the number one position in "outstate
Illinois," which excludes the nine counties that comprise the Chicago market.

The merger, which was announced February 2, 1998, received regulatory approval
on June 2, 1998. The merger was accounted for as a pooling of interests.

Mercantile also announced today the completion of its merger with CBT
Corporation, headquartered in Paducah, Kentucky.

With assets of $32 billion, Mercantile is the largest locally managed and
independently owned financial services organization headquartered in the lower
Midwest, and the twenty-sixth largest bank holding company in the United States.
Mercantile currently has acquisitions pending with Financial Services
Corporation of the Midwest, headquartered in Rock Island, Illinois, and First
Financial Bancorporation, headquartered in Iowa City, Iowa.

MERCANTILE BANCORPORATION INC., a $32 billion multi-bank holding company
headquartered in St. Louis, operates banks in more than 500 locations throughout
Missouri, Iowa, Kansas, Illinois, Arkansas and Kentucky. Mercantile currently
has acquisitions pending with Financial Services Corporation of the Midwest,
headquartered in Rock Island, Illinois, and First Financial Bancorporation,
headquartered in Iowa City, Iowa. Mercantile's non-banking subsidiaries include
companies providing brokerage services, asset-based lending, factoring,
investment advisory services, leasing services and credit life and other
insurance products as agent.

SOURCE MERCANTILE BANCORPORATION INC.

/CONTACT: Beth Fagan, Public Affairs, 314-418-8174, or Mary K. Granberg,
Investor Relations, 314-418-8237, both of MERCANTILE BANCORPORATION/

/Company News On-Call: http://www.prnewswire.com or fax, 800-758-5804,
ext. 107087/

(MTL)