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                                                               EXHIBIT 5(a)


                                           July 26, 1996




Bank of Boston Corporation
100 Federal Street
Boston, Massachusetts 02110

      Re:      BANK OF BOSTON CORPORATION'S REGISTRATION STATEMENT ON FORM S-8
               RELATING TO THE 1978 STOCK OPTION PLAN FOR KEY EMPLOYEES OF
               BAYBANKS, INC. AND AFFILIATES, THE 1988 STOCK OPTION PLAN FOR KEY
               EMPLOYEES OF BAYBANKS, INC. AND AFFILIATES AND THE BAYBANKS, INC.
               SAVINGS, PROFIT SHARING AND STOCK OWNERSHIP PLAN

      As General Counsel of Bank of Boston Corporation (the "Corporation") and
The First National Bank of Boston (the "Bank"), I, and other attorneys in this
office, have participated with the Corporation, its officers and officers of the
Bank in the preparation for filing with the Securities and Exchange Commission
(the "Commission") of a Registration Statement on Form S-8 (the "Registration
Statement") covering (i) an aggregate of 750,000 shares (the "Shares") of the
Corporation's Common Stock, par value $1.50 per share, which Shares may
hereafter be acquired by participants ("Participants") in the 1978 Stock Option
Plan for Key Employees of BayBanks, Inc. and Affiliates and the 1988 Stock
Option Plan for Key Employees of BayBanks, Inc. and Affiliates (collectively,
the "Option Plans") and the BayBanks, Inc. Savings, Profit Sharing and Stock
Ownership Plan (the "Savings Plan" and, collectively with the Option Plans, the
"Plans") and (ii) an indeterminate amount of interests ("Interests") in the
Savings Plan, which Interests may hereafter be acquired by Participants in the
Savings Plan. In connection with filing the Registration Statement, the rules
and regulations of the Commission require my opinion, in my capacity as General
Counsel of the Corporation, on the matters set forth below.

      In rendering this opinion, I, and other attorneys in this office working
under my supervision, have examined and relied upon originals or copies,
certified or otherwise, of all such corporate records, documents, agreements or
other instruments of the Corporation, and have made such investigation of law
and have discussed with the officers of the Corporation and the Bank such
questions of fact as we have deemed necessary or appropriate. In rendering this
opinion, I have relied upon certificates and statements of officers and
directors of the Corporation and the Bank as to factual matters, and have
assumed the genuineness of all documents submitted as copies. Moreover, as to
(ii) below, I have relied upon the opinion of Mintz, Levin, Cohn, Ferris,
Glovsky and Popeo, P.C., special counsel to BayBanks, Inc.


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Bank of Boston Corporation           - 2 -                   July 26, 1996


      Based upon and subject to the foregoing, I am of the opinion that (i) the
Shares will be, upon the issuance thereof pursuant to the terms of the Plans,
legally issued, fully paid and non-assessable and (ii) the Savings Plan confers
valid Interests upon Participants in the plan, to the extent and upon the terms
and conditions described in such plan.

      I hereby consent to the use of this opinion as an exhibit to the
Registration Statement and to the use of my name in the Registration Statement
under the caption "Interests of Named Experts and Counsel."


                                          Very truly yours,

                                          /s/ GARY A. SPIESS

                                          Gary A. Spiess
                                          General Counsel

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              MINTZ, LEVIN, COHN, FERRIS, GLOVSKY AND POPEO, P.C.
                              One Financial Center
                          Boston, Massachusetts 02111


701 Pennsylvania Avenue, N. W.                         Telephone: 617/542-6000
Washington, D.C. 20004                                 Fax: 617/542-2241
Telephone: 202/434-7300
Fax: 202/434-7400

C. Stephen Parker, Jr.                                 Direct Dial Number
                                                       617/348-1707


                                 July 24, 1996


Gary A. Spiess
General Counsel
Bank of Boston Corporation
100 Federal Street
Boston, MA  02110

     RE:    BAYBANKS, INC. SAVINGS, PROFIT SHARING AND
            STOCK OWNERSHIP PLAN

Dear Mr. Spiess:

     We are rendering this opinion in connection with the Registration
Statement on Form S-8 (the "Registration Statement") which we understand
will be filed by Bank of Boston Corporation (the "Corporaton") with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended,  covering among other things certain shares of common
stock of the Corporation and certain interests in the BayBanks Savings, Profit
Sharing and Stock  Ownership Plan (the "Savings Plan"). We understand that the
Registration  Statement will be filed with the Commission at some point shortly
before the effectiveness of the merger of a wholly-owned subsidiary of the
Corporation with and into BayBanks, Inc., pursuant to the Agreement and Plan of
Merger by and among the Corporation, Boston Merger Corp., and BayBanks, Inc.
dated as of December 12, 1995.

     We have acted as special counsel for BayBanks, Inc. with respect to certain
matters relating to the Savings Plan, including the preparation of amendments
to the Savings Plan and the making of certain filings with the Internal Revenue
Service in connection with obtaining a favorable determination letter concerning
the qualified status of the Savings Plan and its related trust under Sections
401(a) and 501(a) of the Internal Revenue Code of 1986, as amended. We have 
examined such documents and taken such additional steps as we consider necessary
to enable us to render this opinion.

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Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.


Gary A. Spiess
July 24, 1996
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     Based upon the foregoing, we are of the opinion that the Savings Plan 
confers legal and valid interests upon participants therein to the extent and
upon the terms and conditions provided in the Savings Plan.

     We hereby consent to the use of this opinion as an exhibit to the 
Registration Statement.


                                             Very truly yours,


                                             /s/ Mintz, Levin, Cohn, Ferris, 
                                                 Glovsky and Popeo, P.C.