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                         [STOCK CERTIFICATE BACKGROUND]

                                                                     EXHIBIT 4.1

                          [MEDFORD BANCORP, INC. LOGO]


        INCORPORATED UNDER THE LAWS OF THE COMMONWEALTH OF MASSACHUSETTS

      THIS CERTIFICATE IS TRANSFERABLE IN BOSTON, MA OR NEW YORK CITY, NY

       COMMON STOCK                                                COMMON STOCK
     PAR VALUE $0.50                                             PAR VALUE $0.50



THIS CERTIFIES that                                            CUSIP 584131 10 6


                                             SEE REVERSE FOR CERTAIN DEFINITIONS
                                             AND FOR INFORMATION WITH RESPECT TO
                                             CERTAIN REFERENCES WHICH MAY EXIST
                                             WITH RESPECT TO THE COMMON STOCK












is the owner of



    FULLY PAID AND NON-ASSESSABLE $0.50 PAR VALUE SHARES OF COMMON STOCK OF


     MEDFORD BANCORP, INC. transferable on the books of the Company by the
     holder hereof in person or by duly authorized attorney upon surrender of
     this certificate properly endorsed or assigned. This certificate and the
     shares of common stock represented hereby are issued and shall be held
     subject to the laws of The Commonwealth of Massachusetts and to the Charter
     and By-laws of the Company, as in effect and as amended from time to time
     hereafter. Such shares are not deposit accounts and are not insured by the
     Federal Deposit Insurance Corporation, the Massachusetts Mutual Savings
     Central Fund, Inc. or any other insurer. This certificate is not valid
     until countersigned and registered by the Transfer Agent and Registrar.

                                  Witness the facsimile seal of the Company and
                                  the facsimile of its duly authorized officers.

                                  Dated:




[MEDFORD BANCORP, INC. SEAL]      /s/ Phillip W. Wong       /s/ Arthur H. Meehan
                                  Philip W. Wong            Arthur H. Meehan
                                  Treasurer                 President

   2
                             MEDFORD BANCORP, INC.



     The shares of common stock represented by this certificate are issued and
shall be held subject to all the provisions of the Charter and By-laws of the
Company, as in effect and as amended from time to time hereafter, to all of
which the holder by acceptance hereof assents. The Company will furnish to any
stockholder upon written request and without charge, a copy of the Charter and
By-laws of the Company. Such request may be made to the Shareholder Relations
Department.

     The Charter authorizes the issuance of shares of preferred stock in one or
more series with such voting, dividend, dissolution and other rights and
preferences as specified by the Board of Directors of the Company at the time of
issuance of the shares. The Charter, in accordance with Massachusetts
regulations, also provides for a liquidation account for the benefit of certain
account holders of Medford Savings bank (the "Bank") as of July 31, 1985 who
continue to maintain their accounts at the Bank, which holders have priority
rights over the common stockholders of the Company in the event of a complete
liquidation of the Bank. A statement of the preferences, powers, qualifications
and rights of the series and classes of such stock and of the terms of the
liquidation account will be furnished to the holder of this certificate upon
written request and without charge.

     The following abbreviations, when used in the inscription on the face of
this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations.


                                                      

     TEN COM - as tenants in common                      UNIF GIFT MIN ACT - __________ Custodian ___________
     TEN ENT - as tenants by the entireties                                     (Cust)               (Minor)
     JT TEN  - as joint tenants with right                                   Under Uniform Gifts to Minors
               of survivorship and not as                                    Act _________
               tenants in common                                                  (State)



    Additional abbreviations may also be used though not in the above list.


     For value received, _______________________________ hereby sell, assign
and transfer unto

 PLEASE INSERT SOCIAL SECURITY OR OTHER
     IDENTIFYING NUMBER OF ASSIGNEE
 ______________________________________
|                                      |
|______________________________________|________________________________________

________________________________________________________________________________

________________________________________________________________________________
Please print or typewrite name and address including postal zip code of assignee

________________________________________________________________________________

________________________________________________________________________________
represented by the within certificate, and do hereby irrevocably constitute and
appoint

_______________________________________________________________________ Attorney
to transfer the said shares on the books of the within-named Company with full
power of substitution in the premises.

Dated ______________________

                                  _____________________________________________
                                  NOTICE: The signature to this assignment must
                                  correspond with the name as written upon the
                                  face of the certificate in every particular,
                                  without alteration or enlargement, or any
                                  change whatever.

Signature Guaranteed: _______________________________________________
                      ALL GUARANTEES MUST BE MADE BY A FINANCIAL
                      INSTITUTION (SUCH AS A BANK OR BROKER) WHICH IS
                      A PARTICIPANT IN THE SECURITIES TRANSFER AGENTS
                      MEDALLION PROGRAM ("STAMP"). THE NEW YORK STOCK
                      EXCHANGE, INC. MEDALLION SIGNATURE PROGRAM
                      ("MSP") OR THE STOCK EXCHANGE MEDALLION PROGRAM
                      ("SEMP") AND MUST NOT BE DATED. GUARANTEES BY A
                      NOTARY PUBLIC ARE NOT ACCEPTABLE.

This certificate also evidences and entitles the holder hereof to certain Rights
as set forth in an Amended and Restated Shareholder Rights Agreement among
Medford Bancorp, Inc., Medford Savings bank, and State Street Bank and Trust
Company, as Rights Agent, dated as of November 26, 1997, as amended, restated,
renewed or extended from time to time (the "Rights Agreement"), the terms of
which are hereby incorporated herein by reference and a copy of which is on
file at the principal offices of Medford Bancorp, Inc. and the stock transfer
administration office of the Rights Agent. Under certain circumstances, as set
forth in the Rights Agreement, such Rights will be evidenced by separate
certificates and will no longer be evidenced by this certificate. Medford
Bancorp, Inc. may redeem the Rights at a redemption price of $.01 per Right,
subject to adjustment, under the terms of the Rights Agreement. Medford
Bancorp, Inc. will mail to the holder of this certificate a copy of the Rights
Agreement, as in effect on the date of mailing, without charge promptly after
receipt of a written request therefor. Under certain circumstances, Rights
issued to or held by Acquiring Persons, Adverse Persons or any Affiliates or
Associates thereof (as defined in the Rights Agreement), and any subsequent
holder of such Rights, may become null and void. The Rights shall not be
exercisable, and shall be void so long as held, by a holder in any jurisdiction
where the requisite qualification, if any, to the issuance to such holder, or
the exercise by such holder, of the Rights in such jurisdiction shall not have
been obtained or be obtainable.