As filed with the Securities and Exchange Commission on December 23, 1997.
                                                              File No. 333-____
  ---------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-3
            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
                        --------------------------------
                                   UST CORP.
             (Exact name of Registrant as specified in its charter)

        MASSACHUSETTS                                   04-2436093
(State or other jurisdiction                          (I.R.S. Employer
       of organization)                               Identification No.)

          40 COURT STREET, BOSTON, MASSACHUSETTS 02108 (617) 726-7000
   (Address and telephone number of registrant's principal executive offices)
                        --------------------------------


             JAMES K. HUNT                        ERIC R. FISCHER, ESQ.
        Executive Vice President               Executive Vice President,
  Chief Financial Officer and Treasurer       General Counsel and Clerk
               UST CORP.                              UST CORP.
            40 Court Street                       40 Court Street
      Boston, Massachusetts 02108             Boston, Massachusetts 02108
            (617) 726-7055                          (617) 726-7377

           (Name, address and telephone number of agent for service)


        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
   As soon as practicable after this Registration Statement becomes effective

If the only securities being registered on this form are being offered pursuant
to dividend or interest reinvestment plans, please check the following box.[ ]
If any of the securities being registered on this form are to be offered
on a delayed or continuous basis pursuant to Rule 415 under the Securities Act
of 1933, check the following box. [X]
If this Form is filed to register additional securities for an offering pursuant
to Rule 462(b) under the Securities Act, please check the following box and list
the Securities Act registration statement number of the earlier effective
registration statement for the same offering.[ ]
If this Form is a post-effective amendment filed
 pursuant to Rule 462(c) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. [ ]
If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. [ ]

                        CALCULATION OF REGISTRATION FEE


  
                                              Proposed Maximum   Proposed Maximum
Title of Securities           Amount to       Offering Price     Aggregate          Amount of
to be Registered              be Registered   Per Share*         Offering Price*    Registration Fee

                                                                            
Common Stock
Par Value $0.625 per share    1,180,000       $27.375            $32,302,500           $9529.24
   
  


     *Estimated solely for the purpose of determining the registration fee.
Calculated in accordance with Rule 457(c) based on the average of the high and
low prices reported in the consolidated trading system on December 19, 1997.

     THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SECTION 8(A), MAY
DETERMINE.




INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A
REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT BECOMES
EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE SECURITIES
IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.

                 Subject to Completion, Dated December 23, 1997
                              P R O S P E C T U S
                                   UST CORP.

                              1,180,000 Shares of
                         Common Stock, $0.625 Par Value

                                  -----------

     This Prospectus ("Prospectus") of UST Corp., a Massachusetts corporation
(the "Company" or "UST Corp."), relates to up to 1,180,000 shares (the
"Shares") of the Company's common stock, par value $0.625 per share (the
"Common Stock"), being sold by certain stockholders of the Company (the
"Selling Stockholders"), for their respective accounts. See "Selling
Stockholders." The Company will not receive any proceeds from the sale of
Shares by the Selling Stockholders. The Common Stock is traded on the Nasdaq
National Market under the symbol "USTB." On December 19, 1997, the last
reported sale price of the Common Stock on the Nasdaq National Market was
$27.15625 per share.

     The Company will pay all of the expenses estimated to be $50,000
incident to the registration, offering and sale of the Shares to the public
hereunder (other than commissions, fees and discounts of underwriters, brokers,
dealers and agents). The Company has agreed to indemnify the Selling
Stockholders against certain liabilities, including liabilities under the
Securities Act of 1933 (the "Securities Act").

     All or a portion of the Shares may be disposed of by the Selling
Stockholders hereunder from time to time in one or a combination of the
following transactions: (a) transactions (which may involve block transactions)
on the Nasdaq National Market, or otherwise, at market prices prevailing at the
time of sale or at prices related to such prevailing market prices; or (b)
privately negotiated transactions at negotiated prices, including underwritten
offerings. The Selling Stockholders may effect such transactions by selling the
Shares directly to purchasers or by selling the shares to or through
underwriters, brokers or dealers, and such underwriters, brokers or dealers may
receive compensation in the form of discounts, concessions or commissions from
the Selling Stockholders or the purchasers of the Shares for whom such
underwriters, brokers or dealers may act as agent, or to whom they sell as
principal, or both (which compensation to a particular underwriter, broker or
dealer might be in excess of customary commissions or be changed from time to
time). The Selling Stockholders and the underwriters, brokers, dealers or
agents who participate in a sale of the Shares may be deemed "underwriters"
within the meaning of Section 2(11) of the Securities Act and the commissions
paid or discounts allowed to any of the underwriters, brokers, dealers or
agents in addition to any profits received on resale of the Shares if any of
the underwriters, brokers, dealers or agents should purchase any Shares as a
principal may be deemed to be underwriting discounts or commissions under the
Securities Act. See "Plan of Distribution."

     Certain of the underwriters, brokers, dealers or agents may have other
business relationships with the Company and/or its affiliates in the ordinary
course.



                                  -----------


   THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES
       AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS
         THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
            COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS
               PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS
                              A CRIMINAL OFFENSE.

                                  -----------

     No dealer, salesperson or other person has been authorized to give any
information or to make any representations not contained in this Prospectus or
any Prospectus Supplement, and, if given or made, such information or
representations must not be relied upon as having been authorized by the
Company. Neither this Prospectus nor any Prospectus Supplement constitutes an
offer to sell or a solicitation of an offer to buy any of the securities
offered hereby in any jurisdiction to any person to whom it is unlawful to make
such an offer in such jurisdiction. Neither the delivery of this Prospectus or
any Prospectus Supplement nor any sale made thereunder shall, under any
circumstances, create any implication that there has been no change in the
affairs of the Company since the date hereof or thereof.

                                  
                               Underwriting Discounts     Proceeds to Selling
              Price to Public     and Commissions            Stockholder

Per Share           (l)              (1)(2)                   (1)(2)
Total               (1)              (1)(2)                   (1)(2)


(1) The Selling Stockholders may from time to time effect the sale of the
    Shares at prices and at terms then prevailing or at prices related to the
    then-current market price, or in negotiated transactions. Under the
    securities laws of certain states, the Shares may be sold in such states
    only through registered or licensed brokers or dealers. See "Plan of
    Distribution" and "Selling Stockholders."

(2) The Company has agreed to prepare and file this Prospectus and the related
    Registration Statement and supplements and amendments thereto required by
    the Securities Act with the Securities and Exchange Commission, and to
    deliver copies of the Prospectus to the Selling Stockholders. The expenses
    incurred in connection with the same, estimated at $50,000, will be
    borne by the Company. The Selling Stockholders and any broker-dealers,
    agents or underwriters who participate in a sale of the Shares may be
    deemed "underwriters" within the meaning of the Securities Act, and any
    commissions paid or discounts allowed to, and any profits received on
    resale of the Shares by, any of them may be deemed to be underwriting
    discounts or commissions under the Securities Act. See "Plan of
    Distribution." The Company will not be responsible for any discounts,
    concessions, commissions or other compensation due to any broker or dealer
    in connection with the sale of any of the shares offered hereby, which
    expenses will be borne by the Selling Stockholders.
               
               The date of this Prospectus is December 23, 1997.




                             AVAILABLE INFORMATION

     The Company is subject to the reporting requirements of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and in accordance
therewith files periodic reports and other information with the Securities and
Exchange Commission (the "Commission"). Such reports, proxy statements and
other information concerning the Company may be inspected and copies may be
obtained (at prescribed rates) at public reference facilities maintained by the
Commission at Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C. 20549
and at the regional offices of the Commission located at Seven World Trade
Center, 13th Floor, New York, New York 10048 and at Northwest Atrium Center,
500 W. Madison Street, Suite 1400, Chicago, Illinois 60661-2511. In addition,
electronically filed documents, including reports, proxy and information
statements and other information regarding the Company, can be obtained from
the Commission's Web site at http://www.sec.gov. The Company's Common Stock is
listed on the Nasdaq National Market, and reports, proxy statements and other
information concerning the Company can also be inspected the offices of the
National Association of Securities Dealers, Inc. at 1735 K Street, Washington,
D.C. 20006.

     The Company has filed a Registration Statement on Form S-3 (the
"Registration Statement") under the Securities Act with the Commission with
respect to the Common Stock being offered pursuant to this Prospectus. As
permitted by the rules and regulations of the Commission, this Prospectus omits
certain of the information contained in the Registration Statement. For further
information with respect to the Company and the Common Stock being offered
pursuant to this Prospectus, reference is hereby made to such Registration
Statement, including the exhibits filed as part thereof. Statements contained
in this Prospectus concerning the provisions of certain documents filed with,
or incorporated by reference in, the Registration Statement are not necessarily
complete, each such statement being qualified in all respects by such
reference. Copies of all or any part of the Registration Statement, including
the documents incorporated by reference therein or exhibits thereto, may be
obtained upon payment of the prescribed rates at the offices of the Commission
set forth above.

     Upon request, the Company will provide without charge to each person to
whom a copy of this Prospectus has been delivered a copy of any information
that was incorporated by reference in the Prospectus (other than exhibits to
documents, unless such exhibits are specifically incorporated by reference into
the Prospectus). The Company will also provide upon specific request, without
charge to each person to whom a copy of this Prospectus has been delivered, a
copy of all documents filed from time to time by the Company with the
Commission pursuant to the Exchange Act. Requests for such copies should be
directed to Eric R. Fischer, Executive Vice President, General Counsel and
Clerk of UST Corp., 40 Court Street, Boston, MA 02108. Telephone requests may
be directed to Mr. Fischer at (617) 726-7377.

                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     There is incorporated herein by reference the Annual Report on Form 10-K
of the Company for the fiscal year ended December 31, 1996 and the Quarterly
Reports on Form 10-Q of the Company for the fiscal quarters ended March 31,
1997, June 30, 1997 and September 30, 1997 filed with the Commission pursuant
to Section 13(a) of the Exchange Act, the Current Report on Form 8-K/A of the
Company for the date July 2, 1996, as amended on February 7, 1997, the Current
Report on Form 8-K/A of the Company for the date August 30, 1996, as amended on
February 7, 1997, the Current Report on Form 8-K/A of the Company for the date
August 30, 1996, as amended on March 4, 1997 and the Current Report on Form 8-K
of the Company for the date December 16, 1997 filed with the Commission
pursuant to Section 13(a) of the Exchange Act, and the description of the
Common Stock contained in the Company's Registration Statement filed with the
Commission under to Section 12(g) of the Exchange Act including any amendment
or report filed for the purpose of updating such description.

     All documents filed by the Company pursuant to Sections 13(a), 13(c), 14
or 15(d) of the Exchange Act subsequent to the date of this Prospectus and
prior to the termination of the offering of the Common Stock shall be deemed to
be incorporated by reference in this Prospectus and to be a part hereof from
the date of filing such documents. Any statement contained herein or in a
document, all or a portion of which is incorporated or deemed to be
incorporated by reference herein, shall be deemed to be modified or superseded



for purposes of this Prospectus to the extent that a statement contained herein
or in any other subsequently filed document or portion thereof which also is or
is deemed to be incorporated by reference herein modifies or supersedes such
statement. Any such statement so modified or superseded shall not be deemed,
except as so modified or superseded, to constitute a part of this Prospectus.

                              CAUTIONARY STATEMENT

     The documents incorporated by reference in this Prospectus contain, and
additional statements issued by the Company from time to time in public filings
or press releases or publicly made orally by officers of the Company with
respect to the Company contain or may contain, "forward-looking statements"
within the meaning of the Private Securities Litigation Reform Act of 1995.
Such statements are subject to certain risks and uncertainties, including
without limitation those discussed in the Company's 1996 Annual Report to
Shareholders and Quarterly Reports on Form 10-Q for the quarters ended March
31, 1997, June 30, 1997 and September 30, 1997. Such forward-looking statements
speak only as of the date on which they are made, and the Company cautions
readers not to place undue reliance on such statements. All forward-looking
information is inherently uncertain and actual results may differ materially
from the assumptions, estimates or expectations reflected or contained in the
forward-looking information.

                                  THE COMPANY

     UST Corp., a bank holding company registered with the Board of Governors
of the Federal Reserve System (the "Federal Reserve Board"), was organized as a
Massachusetts business corporation in 1967. The Company is also subject to
examination by, and is required to file reports with, the Commissioner of Banks
of the Commonwealth of Massachusetts (the "Massachusetts Commissioner"). As of
December 31, 1996, the Company's banking subsidiaries were USTrust and United
States Trust Company ("USTC"), each headquartered in Boston. USTrust and USTC
are sometimes hereinafter collectively referred to as the "Subsidiary Banks."
Subsequently, on January 3, 1997, the Company acquired Walden Bancorp, Inc. of
Acton, Massachusetts ("Walden"), and its subsidiary banks, The Co-operative
Bank of Concord ("Concord"), headquartered in Concord, and The Braintree
Savings Bank ("Braintree") headquartered in Braintree. During the second
quarter of 1997, Concord and Braintree, former subsidiaries of Walden, were
merged with and into USTrust, the principal banking subsidiary of UST Corp. The
Company's acquisition of Walden is discussed in further detail in the Company's
Annual Report on Form 10-K under the caption "Recent Developments - Acquisition
of Walden Bancorp, Inc." and the merger of Braintree, Concord and USTrust is
described in the Company's Form 10-Q for the quarter ended June 30, 1997. Each
of the Company's Subsidiary Banks are chartered under Massachusetts law. All of
the capital stock of the Subsidiary Banks is owned directly or indirectly by
the Company. In addition, the Company owns directly or indirectly through its
banking subsidiaries, all of the outstanding stock of five active nonbanking
subsidiaries, all Massachusetts corporations: UST Leasing Corporation, UST
Capital Corp., UST Securities Corp., USTrust Securities Corp. and UST Auto
Lease Corp., as well as five subsidiaries which hold foreclosed real estate. As
a result of the Walden acquisition, the Company also acquired Concord's two
nonbanking subsidiaries, Walden Financial Corp. and Walden Securities Corp., as
well as one subsidiary which holds foreclosed real estate, and Braintree's
nonbanking subsidiary, Braintree Securities Corp., as well as two subsidiaries
which hold foreclosed real estate. On October 15, 1997, the Company acquired
Firestone Financial Corp. ("Firestone") of Newton, Massachusetts, a small
business equipment finance company. The Company's acquisition of Firestone is
discussed in further detail below under the caption "Recent Developments -
Firestone."

     The Company engages in one line of business, that of providing financial
services through its banking and nonbanking subsidiaries. A broad range of
financial services is provided principally to individuals and small-and
medium-sized companies in New England including those located in low-and
moderate-income neighborhoods within the Company's defined Community
Reinvestment Act assessment area. In addition, an important component of the
Company's financial services is the provision of trust and money management
services to professionals, corporate executives, nonprofit organizations, labor
unions, foundations, mutual funds and owners of closely-held businesses most of
whom are located in the New England region.

     The executive office of UST Corp. is located at 40 Court Street, Boston,
Massachusetts 02108 (Telephone (617) 726-7000).




The Subsidiary Banks

     The Subsidiary Banks are engaged in a general banking business and accept
deposits which are insured by the Federal Deposit Insurance Corporation
("FDIC"). USTC, which has full banking powers and accepts deposits which are
insured by the FDIC, focuses its activity on trust and money management,
venture capital and other fee-generating businesses. USTrust and USTC are
commercial banks. The Subsidiary Banks are both located in Massachusetts.

     For the quarter ended September 30, 1997, the Company reported net income
of $10.8m, or $0.37 per share, compared with net income of $16.0 million, or
$0.57 per share, for the same period of 1996. The third quarter results in 1996
reflect a $14.6 million pre-tax earnings credit that was recorded through the
provision for possible loan losses and a one-time charge of $3.0 million to
reflect the Company's liability for an assessment on certain deposits insured
by the Savings Association Insurance Fund. For the nine months ended September
30, 1997, net income was $19.4 million, or $0.67 per share, compared with $35.2
million, or $1.24 per share, for the first three quarters of 1996. Results for
the 1997 period include a non-recurring charge of $3.1 million for certain
non-deductible merger-related expenses (in respect of the Walden and Firestone
acquisitons) and a pre-tax charge of $11.8 million for restructuring expenses
associated with the acquisition of Walden, accounted for as a pooling of
interest and completed in January, 1997. Results for the 1996 period include
the aforementioned $14.6 million pre-tax earnings credit, a similar $5.2
million credit recorded in the second quarter and the $3.0 million one-time
deposit insurance assessment.

Recent Developments - Firestone

     On August 12, 1997, the Company announced the execution of a definitive
agreement to acquire Firestone, an $85 million small business equipment finance
company headquartered in Newton, Massachusetts. The transaction, which was
consummated on October 15, 1997, was accounted for as a pooling of interests
and was structured as a tax-free exchange of 0.63 shares of UST common stock
for each of the 2.0 million outstanding closely held shares of Firestone common
stock, up to a maximum value of $30 million. At the Company's closing price of
$21.75 on August 8, 1997, the transaction was valued at approximately $27.4
million. Based on the Company's common stock average market value of $25.43
during the determination period set forth in the definitive agreement, the
Company exchanged a total of 1,180,000 shares of common stock, representing an
exchange ratio of 0.59 shares of UST for each share of Firestone. The Company's
common stock exchanged for Firestone common stock was not registered prior to
the effectiveness of the transaction and cannot be offered or resold absent
registration or an applicable exemption from registration requirements. The
Company has recorded a one-time, pre-tax charge of approximately $1 million for
acquisition-related costs in connection with the transaction.

Recent Developments - Somerset

     On December 9, 1997, the Company executed an Affiliation Agreement and
Plan of Reorganization (the "Somerset Agreement") with Somerset Savings Bank
("Somerset"), pursuant to which Somerset will be merged with and into the
Company's wholly-owned principal bank subsidiary, USTrust. Somerset is a
Massachusetts savings bank which serves the consumer and small business banking
needs of its customers through its five branch offices located in the
Massachusetts communities of Somerville and Burlington. The Somerset
transaction, which is structured to qualify as a pooling-of-interests for
accounting purposes, is subject to the approval of the shareholders of Somerset
as well as to the receipt of federal and state regulatory banking approvals.
Subject to the foregoing conditions, the Somerset transaction is expected to
close during the first half of 1998.

     The Somerset transaction is structured as a tax-free exchange of 0.19
shares of the Company's common stock for each share of Somerset's common stock.
At the Company's closing stock price of $29.625 on December 9, 1997, the
Somerset transaction would be valued at approximately $93.7 million, and
Somerset shareholders would receive a value of $5.63 in Company common stock
for each share of Somerset common stock. The purchase price represents a
multiple of 2.43 times stated book value of Somerset at September 30, 1997. The
Company expects to record a one-time pre-tax charge of approximately $7.5
million of acquisition related costs in connection with the Somerset
transaction.

     Immediately after execution of the Somerset Agreement on December 10,
1997, the Company entered into a Stock Option Agreement with Somerset, pursuant
to which Somerset has granted to the Company the option to purchase, under
certain circumstances, 2,777,000 shares of Somerset common stock at an exercise
price of $4.875 per share and has also granted the Company certain additional
consideration related to the option.



Recent Developments - Affiliated

     On December 15, 1997, the Company executed an Affiliation Agreement and
Plan of Reorganization (the "Affiliated Agreement") with Affiliated Community
Bancorp, Inc. ("Affiliated"), pursuant to which the Company will acquire
Affiliated. Affiliated is a $1.1 billion bank holding company for three
community banks, Lexington Savings Bank, The Federal Savings Bank and Middlesex
Bank and Trust Company (together, the "Affiliated Banks") which serve consumer
and small business banking needs through twelve branch offices located in
eastern Middlesex County. The Affiliated transaction, which is structured to
qualify as a pooling-of-interests for accounting purposes, is subject to the
approval of the shareholders of the Company and Affiliated as well as to the
receipt of federal and state regulatory banking approvals. The Affiliated
transaction is expected to close during the first half of 1998. While the
Company will first acquire Affiliated thereby making the Affiliated Banks
subsidiaries of the Company, the Company anticipates merging the banks into its
principal banking subsidiary, USTrust, in 1998.

     The Affiliated transaction is structured as a tax-free exchange of 1.41
shares of the Company's common stock for each share of Affiliated common stock.
At the Company's closing stock price of $28.3125 on December 12, 1997, the
Affiliated transaction would be valued at approximately $259 million, and
Affiliated shareholders would receive a value of $39.92 in Company common stock
for each share of Affiliated common stock. The purchase price represents a
multiple of 2.3 times stated book value of Affiliated at September 30, 1997.
The Company expects to record a one-time pre-tax charge of approximately $12
million of acquisition related costs in connection with the Affiliated
transaction. If the Company's average stock price during a period prior to
closing is less than $24.06 per share and the Company's stock price has
declined by more than 15% relative to a certain bank stock index, Affiliated
can terminate the agreement subject to the right of the Company to issue
additional shares to ensure a per share value of $33.92 in stock of the
Company.

     Immediately after execution of the Affiliated Agreement on December 15,
1997, the Company entered into a Stock Option Agreement with Affiliated
pursuant to which Affiliated has granted to the Company the option to purchase,
under certain circumstances, up to 1,300,078 shares of its outstanding stock
for $32.937 per share.

                              SELLING STOCKHOLDERS

     On October 15, 1997, the Stockholders of Firestone (the "Selling
Stockholders") collectively acquired shares of the Common Stock from the
Company in a transaction exempt from the registration requirement of the
Securities Act, in connection with an Agreement and Plan of Reorganization
dated as of August 12, 1997 (the "Acquisition Agreement") and related Agreement
and Plan of Merger, dated as of October 15, 1997, pursuant to which a
wholly-owned subsidiary of the Company merged into Firestone (with Firestone as
the surviving entity), in exchange for shares of the Common Stock.

     The term Selling Stockholders includes the holders listed below and the
beneficial owners of the Shares and their transferees, pledgees, donees and
other successors.

     Pursuant to the Acquisition Agreement, the Company agreed to file with the
Commission the Registration Statement, of which this Prospectus is a part, with
respect to the resale of the Shares. The Company has committed to keep the
Registration Statement effective until the earlier of (i) the first anniversary
of the closing date under the Acquisition Agreement, or (ii) such time as all
the shares of Common Stock covered by such Registration Statement have been
sold. The Company has agreed to indemnify the Selling Stockholders and its
officers, directors and controlling persons against certain liabilities,
including certain liabilities under the Securities Act.

     As of October 14, 1997, except as noted below, none of the Selling
Stockholders held of record any shares of the Company's outstanding Common
Stock. Except as noted below, no Selling Stockholder has, within the past three
years, had any position, office or other material relationship with the Company
or its affiliates.

     As of December 19, 1997, there were 29,719,593 shares of the Common
Stock issued and outstanding.

     The following table sets forth certain information regarding the
beneficial ownership of the Common Stock as of December 17, 1997 and as
adjusted to reflect the sale of all of the Common Stock offered hereby by the
Selling Stockholders.



    Name of Selling          Shares Owned        Shares      Shares to be Owned
     Stockholders         Prior  to Offering   Offered (1)     After Offering
   -----------------      ------------------  ------------     -------------
                                               
                               
1. Michael A. Miller (2)       297,360 (3)      297,360            -0-
   199 Temple Street
   West Newton, MA 02165

2. MAM Family Limited          236,000          236,000            -0-
     Partnership
   199 Temple Street
   West Newton, MA 02165

3. Robert D. Fanger (4)        312,700          312,700            -0-
   190 Dudley Street
   Brookline, MA 02146

4. Edward S. Yaffe (5)         118,500 (6)      118,000           500
   47 Castle Drive
   Sharon, MA 02067

5. David S. Cohen (7)          118,500 (8)      118,000           500
   2 Savel Lane
   Sharon, MA 02067

6. Michael A. Guidi (9)         59,000           59,000            -0-
   62 Laurelwood Drive
   Hopedale, MA 01747

7. Scott A. Cooper (10)         17,700           17,700            -0-
   52 Williams Road
   Sharon, MA 02067

8. Joan G. Corbett (11)         11,800           11,800            -0-
   16 Harding Street
   Medfield, MA 02052

9. Mary Teresa Crealese         11,800           11,800            -0-
   15 Deerfield Drive
   Bridgewater, MA 02324


      (1)  See "Plan of Distribution."

      (2)  Effective  November  1,  1997,  Michael  A.  Miller  became a
Director of the  Company.  Mr.  Miller is also the  President  and Chief
Executive Officer of Firestone.

      (3) Michael A. Miller is a General Partner of the MAM Family Limited
Partnership, through which he controls one percent (1%) of the 236,000 shares
of Common Stock owned by the MAM Family Limited Partnership, or 2,360 shares.
Such shares are included here as "Shares Owned," but Mr. Miller disclaims any
beneficial ownership of such shares.

      (4)  Robert D. Fanger was an employee of Firestone  until  October
1997.  Mr.  Fanger was also the  Chairman of the Board of  Directors  of
Firestone,   and  resigned  upon  the  closing  of  the  acquisition  of
Firestone by the Company.



      (5)  Edward S. Yaffe is a Senior Vice President of Firestone.

      (6) As of October 14, 1997, Edward S. Yaffe owned, and continues to own
as of the date hereof, through a self-directed Individual Retirement Account,
500 shares of Common Stock. Such shares are included here as "Shares Owned,"
but are not offered for sale under this Registration Statement.

      (7)  David  S.  Cohen  is  the  Executive  Vice  President,  Chief
Financial Officer and Treasurer of Firestone.

      (8) David S. Cohen possesses a power of attorney in respect of an
investment account owned by his parents-in-law. Such account currently holds
500 shares of Common Stock. Such shares are included here as "Shares Owned,"
but are not offered for sale under this Registration Statement and Mr. Cohen
disclaims any beneficial ownership of such shares.

      (9)  Michael A. Guidi is a Senior Vice President of Firestone.

      (10) Scott A. Cooper owns, through a self-directed Individual Retirement
Account, 11,800 shares of Common Stock. Such shares are included here as
"Shares Owned," and are offered for sale under this Registration Statement.

      (11) Joan G. Corbett is an employee of Firestone.

                              PLAN OF DISTRIBUTION

     The sale or distribution of the Shares may be effected directly to
purchasers by the Selling Stockholders as a principal or through one or more
underwriters, brokers, dealers or agents from time to time in one or more
transactions (which may involve crosses or block transactions) (i) on any
exchange or in the over-the-counter market, (ii) in transactions otherwise than
in the over-the-counter market or (iii) through the writing of options (whether
such options are listed on an options exchange or otherwise) on, or settlement
of short sales of, the Shares. Any of such transactions may be effected at
market prices prevailing at the time of sale, at prices related to such
prevailing market prices, at varying prices determined at the time of sale or
at negotiated or fixed prices, in each case as determined by the Selling
Stockholders or by agreement between the Selling Stockholders and underwriters,
brokers, dealers or agents, or purchasers. The Selling Stockholders may effect
such transactions by selling the Shares directly to purchasers or by selling
shares to or through underwriters, brokers or dealers and such underwriters,
brokers or dealers may receive compensation in the form of discounts,
concessions or commissions from the Selling Stockholders or the purchasers of
the Shares for whom such underwriters, brokers or dealers may act as agent, or
to whom they sell as principal, or both (which compensation to a particular
underwriter, broker or dealer might be in excess of customary commissions or be
changed from time to time). The Selling Stockholders and any underwriters,
brokers, dealers or agents who participate in a sale of the Shares may be
deemed "underwriters" within the meaning of Section 2(11) of the Securities Act
and the commissions paid or discounts allowed to any of such underwriters,
brokers, dealers or agents in addition to any profits received on resale of the
Shares if any of such underwriters, brokers, dealers or agents should purchase
any Shares as a principal may be deemed to be underwriting discounts or
commissions under the Securities Act.

     Certain of any such underwriters, dealers, brokers or agents may have
other business relationships with the Company and/or its affiliates in the
ordinary course.

     Under the securities laws of certain states, the Shares may be sold in
such states only through registered or licensed brokers or dealers.

     The Company will pay all of the expenses incident to the registration,
offering and sale of the Shares to the public hereunder other than commissions,
fees and discounts of underwriters, brokers, dealers and agents. The Company
has agreed to indemnify the Selling Stockholders and controlling persons
(within the meaning of the Securities Act) against certain liabilities,
including liabilities under the Securities Act.



     If all or a portion of the Shares are offered through an underwritten
offering, the terms of such underwritten offering, including the initial public
offering price, the names of the underwriters and the compensation, if any, of
such underwriters, will be set forth in an accompanying Prospectus Supplement.

     Until the distribution of the Shares is completed, rules of the Commission
may limit the ability of any underwriters and any other person participating in
the distribution of the Shares to bid for and purchase the Common Stock. As an
exception to these rules, underwriters are permitted to engage in certain
transactions that stabilize the price of the Common Stock. Such transactions
consist of bids or purchases for the purpose of pegging, fixing or maintaining
the price of the Common Stock. If any underwriters create a short position in
the Shares in connection with the offering, selling more Shares than are set
forth on the cover page of this Prospectus, the underwriters may reduce that
short position by purchasing shares of Common Stock in the open market.
Purchases of the Common Stock for the purpose of stabilization or to reduce a
short position could cause the price of the Common Stock to be higher than it
might be in the absence of such purchases. In addition, rules of the Commission
may limit the timing of purchases and sales of shares of Common Stock by the
Selling Stockholders and any other such person. All of the foregoing may limit
the marketability of the Shares and the ability of any underwriter, broker,
dealer or agent to engage in market making activities.

                                USE OF PROCEEDS

     The Company will not receive any of the proceeds from the sale of any of
the Shares by the Selling Stockholders.

                             CERTAIN LEGAL MATTERS

     The validity of the offered Common Stock will be passed upon for the
Company by Eric R. Fischer, Executive Vice President, General Counsel and Clerk
of the Company. As of December 22, 1997, Mr. Fischer had a direct or indirect
interest in 36,798 shares of Common Stock and had options to purchase an
additional 50,800 shares, all of which options were immediately exercisable.

                                    EXPERTS

     The consolidated financial statements of UST Corp. included in its Annual
Report on Form 10-K for the year ended December 31, 1996, and incorporated by
reference in this Prospectus and elsewhere in the Registration Statement, have
been audited by Arthur Andersen LLP, independent public accountants, as
indicated in their report with respect thereto, and are included herein in
reliance upon the authority of said firm as experts in giving said report.





                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14.   Other Expenses of Issuance and Distribution.

     The estimated expenses in connection with the issuance and distribution of
the securities being registered, other than underwriting compensation, are:

           SEC Registration Fee..............................   $   9,529.24
           Transfer Agent and Registrar Fees and Expenses....   $       0.00
           Legal Fees and Expenses...........................   $  10,000.00
           Accounting Fees and Expenses......................   $  10,000.00
           Nasdaq National Market Fee........................   $  17,500.00 
           Miscellaneous.....................................   $   2,970.76
           Total.............................................   $  50,000.00  


     __________________       
     *  Estimates

Item 15.   Indemnification of Directors and Officers.

     Section 67 of Chapter 156B of the Massachusetts General Laws authorizes a
corporation to indemnify any director, officer, employee or other agent of the
corporation to whatever extent specified in or authorized by (a) the articles
of organization, (b) a by-law adopted by the stockholders or (c) a vote adopted
by the holders of a majority of the shares of stock entitled to vote on the
election of directors.

     The Registrant's Articles of Organization provide that the Registrant
shall, to the fullest extent legally permissible, indemnify each person who is
or was a director, officer, employee or other agent of the Registrant and each
person who is or was serving at the request of the Registrant as such of
another corporation or of any partnership, joint venture, trust, employee
benefit plan or other enterprise or organization, against all liabilities,
costs and expenses, including but not limited to amounts paid in satisfaction
of judgments, in settlement or as fines and penalties, and counsel fees and
disbursements, reasonably incurred by him or her in connection with the defense
or disposition of or otherwise in connection with or resulting from any action,
suit or other proceeding, whether civil, criminal, administrative or
investigative, before any court or administrative or legislative or
investigative body, in which he or she may be or may have been involved as a
party or otherwise or with which he or she may be or may have been threatened,
while in office or thereafter, by reason of his or her being or having been
such a director, officer, employee, agent or trustee, or by reason of any
action taken or not taken in any such capacity. Under Massachusetts law and the
Articles, no indemnification may be provided for any person with respect to any
matter as to which he or she shall have been adjudicated in any proceeding not
to have acted in good faith in the reasonable belief that his or her action was
in the best interest of the Registrant or other entity served or, to the extent
that such matter relates to service with respect to an employee benefit plan,
in the best interest of the participants or beneficiaries of such employee
benefit plan.

     If, in an action, suit or proceeding brought by or in the name of the
Registrant, a director of the Registrant is held not liable for monetary
damages, whether because that director is relieved of personal liability under
the provisions of the Articles of Organization, or otherwise, that director
shall be deemed to have met the standard of conduct set forth above and to be
entitled to indemnification for expenses reasonably incurred in the defense of
such action, suit or proceeding.

     As to any matter disposed of by settlement pursuant to a consent decree or
otherwise, no indemnification either for the amount of such settlement or for
any other expenses shall be provided unless such settlement shall be approved
as in the best interests of the Registrant, after notice that it involves such
indemnification, (a) by vote of a majority of the disinterested directors then



in office (even though the disinterested directors be less than a quorum), (b)
by any disinterested person or persons to whom the question may be referred by
vote of a majority of such disinterested directors, or (c) by vote of the
holders of a majority of the outstanding stock at the time entitled to vote for
directors, voting as a single class, exclusive of any stock owned by any
interested person, or (d) by any disinterested person or persons to whom the
question may be referred by vote of the holders or a majority of such stock. No
such approval shall prevent the recovery from any such officer, director,
employee, agent or trustee of any amounts paid to him or her or on his or her
behalf as indemnification in accordance with the preceding sentence if such
person is subsequently adjudicated by a court of competent jurisdiction not to
have acted in good faith in the reasonable belief that his or her action was in
the best interests of the Registrant.

     The right of indemnification provided in the Registrant's Articles of
Organization shall not be exclusive of or affect any other rights to which any
director, officer, employee, agent or trustee may be entitled or which may
lawfully be granted to him or her. Indemnification of a "director", "officer",
"employee", "agent", and "trustee" includes their respective executors,
administrators and other legal representatives. An "interested" person is one
against whom the action, suit or other proceeding in question or another
action, suit or other proceeding on the same or similar grounds is then or had
been pending or threatened, and a "disinterested" person is a person against
whom no such action, suit or other proceeding is then or had been pending or
threatened.

Item 16.   Exhibits.

      2    Agreement and Plan of Reorganization dated as of August 12, 1997, by
           and among the Registrant, Firestone and the Selling Stockholders.

      5    Opinion of Eric R. Fischer, Esq.

      23.1 Consent of Eric R. Fischer (included in Exhibit 5).

      23.2 Consent of Arthur Andersen LLP.

      24   Power of Attorney (included on signature page).


Item 17.   Undertakings.

      (A) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act each filing of the
registrant's annual report pursuant to section 13(a) or section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to section 15(d) of the Exchange Act) that is
incorporated by reference in the registration statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

      (B) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions, or otherwise, the
registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Securities Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.

      (C) The undersigned registrant hereby undertakes:

          (1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this registration statement to include any
material information with respect to the plan of distribution not previously
disclosed in the registration statement or any material change to such
information in the registration statement.



          (2) That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

          (3) To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.

      (D) The undersigned registrant hereby undertakes to deliver or cause to
be delivered with the prospectus, to each person to whom the prospectus is sent
or given, the latest annual report, to security holders that is incorporated by
reference in the prospectus and furnished pursuant to and meeting the
requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of
1934; and, where interim financial information required to be presented by
Article 3 of Regulation S-X is not set forth in the prospectus, to deliver, or
cause to be delivered to each person to whom the prospectus is sent or given,
the latest quarterly report that is specifically incorporated by reference in
the prospectus to provide such interim financial information.



                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Boston and the Commonwealth of Massachusetts as of
December 16, 1997.

                                    UST Corp.


                                    By /s/Eric R. Fischer
                                       --------------------------
                                       Eric R. Fischer
                                       (Executive Vice President,
                                       General Counsel and Clerk)

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated. By so signing, each of the undersigned,
in his or her capacity as a director or officer, or both, as the case may be,
of the Registrant, does hereby appoint Neal F. Finnegan, James K. Hunt and Eric
R. Fischer, and each of them severally, or if more than one acts, a majority of
them, his or her true and lawful attorneys or attorney to execute in his or her
name, place and stead, in his or her capacity as a director or officer or both,
as the case may be, of the Registrant, the Registration Statement on Form S-3
and with respect to the shares of UST Common Stock issued in connection with
this offering and any and all amendments to said Registration Statement and all
instruments necessary or incidental in connection therewith, and to file the
same with the Securities and Exchange Commission. Each of said attorneys shall
have full power and authority to do and perform in the name and on behalf of
each of the undersigned, in any and all capacities, every act whatsoever
requisite or necessary to be done in the premises as fully and to all intents
and purposes as each of the undersigned might or could do in person, hereby
ratifying and approving the acts of said attorneys and each of them.



  
 Signature                       Title                                     Date
                                                                  
                              President and
                              Chief Executive
                              Officer (Principal Executive Officer)
/s/Neal F. Finnegan           and Director                              December 16, 1997
- ----------------------
(Neal F. Finnegan)


                              Executive Vice
                              President, Chief Financial
                              Officer and Treasurer
                              (Principal Financial Officer
                              and Principal Accounting
/s/James K. Hunt              Officer)                                  December 16, 1997
- ----------------------
(James K. Hunt)



/s/Chester G. Atkins          Director                                  December 16, 1997
- ----------------------
(Chester G. Atkins)



/s/David E. Bradbury          Director                                  December 16, 1997
- ----------------------
(David E. Bradbury)




/s/Robert M. Coard            Director                                  December 16, 1997
- ----------------------
(Robert M. Coard) 



/s/Domenic Colasacco          Director                                  December 16, 1997
- ----------------------
(Domenic Colasacco)



/s/Robert L. Culver           Director                                  December 16, 1997
- ----------------------
(Robert L. Culver)



/s/Alan K. DerKazarian        Director                                  December 16, 1997
- ----------------------
(Alan K. DerKazarian)



/s/Donald C. Dolben           Director                                  December 16, 1997
- ----------------------
(Donald C. Dolben)



/s/Edward Guzovsky            Director                                  December 16, 1997
- ----------------------
(Edward Guzovsky)


 
/s/Wallace M. Haselton        Director                                  December 16, 1997
- ----------------------
(Wallace M. Haselton)



/s/Brian W. Hotarek           Director                                  December 16, 1997
- ----------------------
(Brian W. Hotarek)



/s/Francis X. Messina         Director                                  December 16, 1997
- ----------------------
(Francis X. Messina)



/s/Michael A. Miller          Director                                  December 16, 1997
- ----------------------
(Michael A. Miller)



/s/Sydney L. Miller           Director                                  December 16, 1997
- ----------------------
(Sydney L. Miller)




/s/Vikki L. Pryor             Director                                  December 16, 1997
- ----------------------
(Vikki L. Pryor)



/s/Gerald M. Ridge            Director                                  December 16, 1997
- ----------------------
(Gerald M. Ridge)



/s/William Schwartz           Director                                  December 16, 1997
- ----------------------
(William Schwartz)



/s/Barbara C. Sidell          Director                                  December 16, 1997
- ----------------------
(Barbara C. Sidell)



/s/James V. Sidell            Director                                  December 16, 1997
- ----------------------
(James V. Sidell)



/s/Paul D. Slater             Director                                  December 16, 1997
- ----------------------
(Paul D. Slater)



/s/Edward J. Sullivan         Director                                  December 16, 1997
- ----------------------
(Edward J. Sullivan)



                              Director                                  December 16, 1997
- ----------------------
(G. Robert Tod)



/s/Michael J. Verrochi, Jr.   Director                                  December 16, 1997
- ----------------------
(Michael J. Verrochi, Jr.)



/s/Gordon M. Weiner           Director                                  December 16, 1997
- ----------------------
(Gordon M. Weiner)





                                 EXHIBIT INDEX


      Exhibit   Description

      2         Agreement and Plan of Reorganization dated as of
                August 12, 1997, by and among the Registrant,
                Firestone and the Selling Stockholders.

      5         Opinion of Eric R. Fischer, Esq.

      23.1      Consent of Eric R. Fischer (included in Exhibit 5).

      23.2      Consent of Arthur Andersen LLP.

      24        Power  of  Attorney (included on signature page).




                                                                      EXHIBIT 5
                                   UST CORP.
                                40 Court Street
                          Boston, Massachusetts 02108



                               December 22, 1997




UST Corp.
40 Court Street
Boston, Massachusetts  02108

      Re:  UST CORP. REGISTRATION STATEMENT ON FORM S-3
           RELATING TO 1,180,000 SHARES OF COMMON STOCK

Ladies and Gentlemen:

     This opinion is rendered to you in connection with the filing by UST
Corp., a Massachusetts corporation, (the "Corporation") of its Registration
Statement on Form S-3 (the "Registration Statement") with the Securities and
Exchange Commission, relating to the registration under the Securities Act of
1933 of 1,180,000 shares of the Corporation's Common Stock, par value $0.625
per share (the "Common Stock"), filed with Securities and Exchange Commission
on December 22 1997, all of which Shares were issued, as unregistered shares,
on October 15, 1997 pursuant to the Terms of an Agreement and Plan of
Reorganization, dated as of August 12, 1997 (the "Agreement"), among the
Corporation, Firestone Financial Corp. ("Firestone") and each of the
stockholders of Firestone.

     In rendering this opinion as General Counsel of the Corporation, I and an
attorney in my office acting under my direction have participated with the
Corporation and its officers in the preparation, review and filing of the
Registration Statement and the related prospectus (the "Prospectus"), have
examined other corporate documents and records, have made such examination of
law, and have discussed with the officers and directors of the Corporation and
its subsidiaries such questions of fact as we have deemed necessary or
appropriate. We have also relied upon certificates and statements of such
officers and directors as to factual matters and have assumed the genuineness
of all signatures not known to us as well as the authenticity of all documents
submitted to us as copies.

     Subject to the foregoing and to the proposed additional proceedings being
taken as now contemplated prior to the issuance of the Common Stock, it is my
opinion that the Common Stock has been duly authorized and that the Common
Stock are validly issued, fully paid and non-assessable.

     I hereby consent to the filing of this opinion as an Exhibit to the
Registration Statement and to the use of my name in the Registration Statement
and the related Prospectus.


                               Very truly yours,



                               /s/Eric R. Fischer
                               -------------------------
                               Eric R. Fischer,
                               Executive Vice President,
                               General Counsel and Clerk





                                                                   EXHIBIT 23.2

                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent public accountants, we hereby consent to the incorporation by
reference in this Registration Statement on Form S-3 of our report, dated
January 31, 1997, included in UST Corp.'s Annual Report on Form 10-K for the
year ended December 31, 1996 and to all references to our Firm included in this
Registration Statement.


                                    ARTHUR ANDERSEN LLP


Boston, Massachusetts
December 19, 1997