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              CERTIFICATE OF DESIGNATION, PREFERENCES AND
         RIGHTS OF SERIES B JUNIOR PARTICIPATING PREFERRED STOCK
                                   OF
                     MERCANTILE BANCORPORATION INC.


      I, John Q. Arnold, the Vice Chairman and Chief Financial Officer of
Mercantile Bancorporation Inc., a corporation organized and existing under
The General and Business Corporation Law of Missouri, in accordance with the
provisions of Section 351.180.7 thereof, DO HEREBY CERTIFY:

      That, pursuant to the authority conferred upon the Board of Directors
by the Certificate of Incorporation, as amended, of the Company, the said
Board of Directors on May 20, 1998 adopted the following resolution creating
a series of Two Million (2,000,000) shares of voting Preferred Stock
designated as Series B Junior Participating Preferred Stock:

      RESOLVED, that pursuant to the authority vested in the Board of
Directors of the Company in accordance with the provisions of its Certificate
of Incorporation, as amended, a series of voting Preferred Stock of the
Company be and it is hereby created, and that the designation and amount
thereof and the powers, preferences and relative, participating, optional and

other special rights of the shares of such series, and the qualifications,
limitations or restrictions thereof are as follows:

      Section 1.  Designation and Amount.
                  ----------------------

      There shall be a series of the voting preferred stock of the Company
which shall be designated as the "Series B Junior Participating Preferred
Stock," no par value, and the number of shares constituting such series shall
be Two Million (2,000,000).  Such number of shares may be increased or
decreased by resolution of the Board of Directors; provided, however, that no
decrease shall reduce the number of shares of Series B Junior Participating
Preferred Stock to a number less than that of the shares then outstanding
plus the number of shares issuable upon exercise of outstanding rights,
options or warrants or upon conversion of outstanding securities issued by
the Company.

      Section 2.  Dividends and Distributions.
                  ---------------------------

      (A)   Subject to the rights of the holders of any shares of any series
of preferred stock of the Company ranking prior and superior to the Series B
Junior Participating Preferred Stock with respect to dividends, the holders
of shares of Series B Junior Participating Preferred Stock, in preference to
the holders of shares of Common Stock, $.01 par value (the "Common Stock"),
of the Company and of any other junior stock, shall be entitled to receive,
when, as and if declared by the Board of Directors out of funds legally
available for the purpose, quarterly dividends payable in cash on or about
the first day of January, April, July and October in each year (each such
date being referred to herein as a "Quarterly Dividend Payment Date"),
commencing on the first Quarterly Dividend Payment Date after the first
issuance of a share or fraction of a share of Series B Junior Participating
Preferred Stock, in an amount per share (rounded to the nearest cent) equal
to the greater of (a) $1.00 or (b) subject to the provision for adjustment
hereinafter set forth, 100 times the aggregate per share amount of all cash
dividends and 100 times the aggregate per share amount (payable in kind) of
all non-cash dividends or other distributions, other than a dividend payable
in shares of Common Stock or a subdivision of the outstanding shares of
Common Stock (by reclassification or otherwise), declared on the Common Stock



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since the immediately preceding Quarterly Dividend Payment Date or, with
respect to the first Quarterly Dividend Payment Date, since the first
issuance of any share or fraction of a share of Series B Junior Participating
Preferred Stock.  In the event the Company shall at any time after May 20,
1998 (the "Rights Declaration Date") declare or pay any dividend on the
Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of
Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the amount to which holders of shares of Series B Junior
Participating Preferred Stock were entitled immediately prior to such event
under clause (b) of the preceding sentence shall be adjusted by multiplying
such amount by a fraction, the numerator of which is the number of shares of
Common Stock outstanding immediately after such event and the denominator of
which is the number of shares of Common Stock that were outstanding
immediately prior to such event.

      (B)   The Company shall declare a dividend or distribution on the
Series B Junior Participating Preferred Stock as provided in paragraph (A) of
this Section immediately after it declares a dividend or distribution on the
Common Stock (other than a dividend payable in shares of Common Stock);
provided, however, that in the event no dividend or distribution shall have
been declared on the Common Stock during the period between any Quarterly
Dividend Payment Date and the next subsequent Quarterly Dividend Payment
Date, a dividend of $1.00 per share on the Series B Junior Participating
Preferred Stock shall nevertheless be payable on such subsequent Quarterly
Dividend Payment Date.

      (C)   Dividends shall begin to accrue and be cumulative on outstanding
shares of Series B Junior Participating Preferred Stock from the Quarterly
Dividend Payment Date next preceding the date of issue of such shares, unless
the date of issue of such shares is prior to the record date for the first
Quarterly Dividend Payment Date, in which case dividends on such shares shall
begin to accrue from the date of issue of such shares, or unless the date of
issue is a Quarterly Dividend Payment Date or is a date after the record date
for the determination of holders of shares of Series B Junior Participating
Preferred Stock entitled to receive a quarterly dividend and before such
Quarterly Dividend Payment Date, in either of which events such dividends
shall begin to accrue and be cumulative from such Quarterly Dividend Payment
Date.  Accrued but unpaid dividends shall not bear interest.  Dividends paid
on the shares of Series B Junior Participating Preferred Stock in an amount
less than the total amount of such dividends at the time accrued and payable
on such shares shall be allocated pro rata on a share-by-share basis among
all such shares at the time outstanding.  The Board of Directors may fix a
record date for the determination of holders of shares of Series B Junior
Participating Preferred Stock entitled to receive payment of a dividend or
distribution declared thereon, which record date shall be not more than 60
days prior to the date fixed for the payment thereof.


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      Section 3.  Voting Rights.
                  -------------

      The holders of shares of Series B Junior Participating Preferred Stock
shall have the following voting rights:

      (A)   Each share of Series B Junior Participating Preferred Stock shall
entitle the holder thereof to 100 votes on all matters submitted to a vote of
the stockholders of the Company.

      (B)   Except as otherwise provided herein, in the Company's Certificate
of Incorporation or by law, the holders of shares of Series B Junior
Participating Preferred Stock, the holders of shares of Common Stock, and the
holders of shares of any other capital stock of the Company having general
voting rights shall vote together as one class on all matters submitted to a
vote of stockholders of the Company.

      (C)   Except as otherwise set forth herein or in the Company's
Certificate of Incorporation, and except as otherwise provided by law,
holders of Series B Junior Participating Preferred Stock shall have no
special voting rights and their consent shall not be required (except to the
extent they are entitled to vote with holders of Common Stock as set forth
herein) for taking any corporate action.

      Section 4.  Certain Restrictions.
                  --------------------

      (A)   Whenever dividends or distributions payable on the Series B
Junior Participating Preferred Stock as provided in Section 2 are in arrears,
thereafter and until all accrued and unpaid dividends and distributions,
whether or not declared, on shares of Series B Junior Participating Preferred
Stock outstanding shall have been paid in full, the Company shall not:

            (i)   declare or pay dividends on, make any other distributions
on, or redeem or purchase or otherwise acquire for consideration any shares
of stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series B Junior Participating Preferred
Stock;

            (ii)  declare or pay dividends on or make any other distributions
on any shares of stock ranking on a parity (either as to dividends or upon
liquidation, dissolution or winding up) with the Series B Junior
Participating Preferred Stock, except dividends paid ratably on the Series B
Junior Participating Preferred Stock and all such parity stock on which
dividends are payable or in arrears in proportion to the total amounts to
which the holders of all such shares are then entitled;

            (iii) except as permitted in Section 4(A)(iv) below, redeem or
purchase or otherwise acquire for consideration shares of any stock ranking
on a parity (either as to dividends or upon liquidation, dissolution or
winding up) with the Series B Junior Participating Preferred Stock, provided,
however, that the Company may at any time redeem, purchase or otherwise
acquire shares of any such parity stock in exchange for shares of any stock
of the Company ranking junior (either as to dividends or upon dissolution,
liquidation or winding up) to the Series B Junior Participating Preferred
Stock; and

            (iv)  purchase or otherwise acquire for consideration any shares
of Series B Junior Participating Preferred Stock, or any shares of stock
ranking on a parity with the Series B Junior Participating Preferred Stock,
except in accordance with a purchase offer made in writing or by publication
(as determined by the Board of Directors) to all holders of such shares upon
such terms as the


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Board of Directors, after consideration of the respective annual dividend
rates and other relative rights and preferences of the respective series and
classes, shall determine in good faith will result in fair and equitable
treatment among the respective series or classes.

      (B)   The Company shall not permit any subsidiary of the Company to
purchase or otherwise acquire for consideration any shares of stock of the
Company unless the Company could, under paragraph (A) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

      Section 5.  Reacquired Shares.
                  -----------------

      Any shares of Series B Junior Participating Preferred Stock purchased
or otherwise acquired by the Company in any manner whatsoever shall be
retired and canceled promptly after the acquisition thereof.  The Company
shall cause all such shares upon their cancellation to be authorized but
unissued shares of Preferred Stock which may be reissued as part of a new
series of Preferred Stock, subject to the conditions and restrictions on
issuance set forth herein.

      Section 6.  Liquidation, Dissolution or Winding Up.
                  --------------------------------------

      (A)   Upon any liquidation (voluntary or otherwise), dissolution or
winding up of the Company, no distribution shall be made to the holders of
shares of stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series B Junior Participating Preferred
Stock unless, prior thereto, the holders of shares of Series B Junior
Participating Preferred Stock shall have received $100.00 per share, plus an
amount equal to accrued and unpaid dividends and distributions thereon,
whether or not declared, to the date of such payment (the "Series B
Liquidation Preference").  Following the payment of the full amount of the
Series B Liquidation Preference, no additional distributions shall be made to
the holders of shares of Series B Junior Participating Preferred Stock,
unless, prior thereto, the holders of shares of Common Stock shall have
received an amount per share (the "Common Adjustment") equal to the quotient
obtained by dividing  (i) the Series B Liquidation Preference by (ii) 100 (as
appropriately adjusted as set forth in paragraph (C) of this Section 6 to
reflect such events as stock dividends, and subdivisions, combinations and
consolidations with respect to the Common Stock) (such number in clause (ii)
being referred to as the "Adjustment Number").  Following the payment of the
full amount of the Series B Liquidation Preference and the Common Adjustment
in respect of all outstanding shares of Series B Junior Participating
Preferred Stock and Common Stock, respectively, holders of Series B Junior
Participating Preferred Stock and holders of shares of Common Stock shall
receive their ratable and proportionate share of the remaining assets to be
distributed in the ratio of the Adjustment Number to 1 with respect to such
Series B Junior Participating Preferred Stock and Common Stock, on a per
share basis, respectively.

      (B)   In the event there are not sufficient assets available to permit
payment in full of the Series B Liquidation Preference and the liquidation
preferences of all other series of preferred stock, if any, which rank on a
parity with the Series B Junior Participating Preferred Stock, then such
remaining assets shall be distributed ratably to the holders of such parity
shares in proportion to their respective liquidation preferences.  In the
event there are not sufficient assets available to permit payment in full of
the Common Adjustment, then such remaining assets shall be distributed
ratably to the holders of Common Stock.

      (C)   In the event the Company shall at any time after the Rights
Declaration Date declare or pay any dividend on Common Stock payable in
shares of Common Stock, or effect a


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subdivision or combination or consolidation of the outstanding shares of
Common Stock (by reclassification or otherwise than by payment of a dividend
in shares of Common Stock) into a greater or lesser number of shares of
Common Stock, then in each such case the Adjustment Number in effect
immediately prior to such event shall be adjusted by multiplying such
Adjustment Number by a fraction the numerator of which is the number of
shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that are
outstanding immediately prior to such event.

      Section 7.  Consolidation, Merger, etc.
                  --------------------------

      In case the Company shall enter into any consolidation, merger,
combination or other transaction in which the shares of Common Stock are
exchanged for or changed into other stock or securities, cash and/or any
other property, then in any such case the shares of Series B Junior
Participating Preferred Stock shall at the same time be similarly exchanged
or changed in an amount per share (subject to the provision for adjustment
hereinafter set forth) equal to 100 times the aggregate amount of stock,
securities, cash and/or any other property (payable in kind), as the case may
be, into which or for which each share of Common Stock is exchanged or
changed.  In the event the Company shall at any time after the Rights
Declaration Date declare or pay any dividend on Common Stock payable in
shares of Common Stock, or effect a subdivision or combination or
consolidation of the outstanding shares of Common Stock (by reclassification
or otherwise than by payment of a dividend in shares of Common Stock) into a
greater or lesser number of shares of Common Stock, then in each such case
the amount set forth in the preceding sentence with respect to the exchange
or change of shares of Series B Junior Participating Preferred Stock shall be
adjusted by multiplying such amount by a fraction the numerator of which is
the number of shares of Common Stock outstanding immediately after such event
and the denominator of which is the number of shares of Common Stock that are
outstanding immediately prior to such event.

      Section 8.  Redemption.
                  ----------

      The shares of Series B Junior Participating Preferred Stock shall not
be redeemable.

      Section 9.  Ranking.
                  -------

      The Series B Junior Participating Preferred Stock shall rank junior to
all other series of the Company's Preferred Stock as to the payment of
dividends and the distribution of assets, unless the terms of any such series
shall provide otherwise.

      Section 10.  Fractional Shares.
                   -----------------

      Series B Junior Participating Preferred Stock may be issued in
fractions which are integral multiples of one one-hundredth of a share.
Fractions of shares of Series B Junior Participating Preferred Stock may, at
the election of the Company, be evidenced by depositary receipts, pursuant to
an appropriate agreement between the Company and a depositary selected by the
Company.  The holders of such depositary receipts shall have all the rights,
privileges and preferences to which they are entitled as beneficial owners of
the Series B Junior Participating Preferred Stock represented by such
depositary receipts.

      IN WITNESS WHEREOF, I have executed and subscribed this Certificate and
do affirm and acknowledge the foregoing as true under the penalties of
perjury this 22nd day of May, 1998.


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                             By:  /s/ John Q. Arnold
                                 -----------------------------------
                             Name:  John Q. Arnold
                             Title:  Vice Chairman and Chief Financial Officer






State of Missouri   )
                    )     SS.
City of St. Louis   )


      On this 22nd day of May, 1998, before me, Michael J. Marshall, a Notary
Public in and for the State of Missouri, personally appeared John Q. Arnold,
Vice Chairman and Chief Financial Officer of Mercantile Bancorporation Inc.,
known to me to be the person who executed the foregoing Certificate of
Designation and acknowledged to me that he executed the same pursuant to
authority given by the Board of Directors of such corporation as their free
and voluntary act, and as the free and voluntary act and deed of such
corporation, for the uses and purposes therein set forth.


                             /s/ Michael J. Marshall
                             ---------------------------------------
                             Notary Public
My commission expires:

January 31, 2000



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