Document:

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                                                                   Exhibit 10.23

                                FOURTH AMENDMENT
                                ----------------

          FOURTH AMENDMENT (this "Amendment"), dated as of March 15, 2001, among
Waters Corporation ("Holdings"), Waters Technologies Corporation (the
"Borrower"), the lenders listed on the signature pages hereof (the "Banks"), and
Bankers Trust Company, as Agent (in such capacity, the "Agent").  All
capitalized terms used herein and not otherwise defined herein shall have the
respective meanings provided for such terms in the Credit Agreement referred to
below.

                                  WITNESSETH:
                                  -----------

          WHEREAS, Holdings, the Borrower, the Banks of the Credit Agreement and
the Agent are parties to a Credit Agreement, dated as of November 22, 1995 and
amended and restated as of June 16, 1997 ( as further amended, modified and
supplemented to date, the "Credit Agreement"); and

          WHEREAS, the parties hereto wish to amend the Credit Agreement as
herein provided;

          NOW, THEREFORE, it is agreed:

          1.   Section 6.20 of the Credit Agreement is hereby amended by
inserting the text "liabilities incurred under Section 8.04 (m) and" immediately
after the text "other than" appearing in the second parenthesis appearing
therein.

          2.   Section 8.01(b) of the Credit Agreement is hereby amended by
deleting the reference to "and (k)" at the end of clause (ii) thereof, and
inserting in lieu thereof the text ", (k) and (m)".

          3.   Section 8.04 of the Credit Agreement is hereby amended by
deleting sub-clause (m) thereof in its entirety and inserting the following new
sub-clause (m) in lieu thereof:

     "(m)   Indebtedness of Holdings and its Subsidiaries consisting of
guaranties of the lease payments owing by their customers in connection with
vendor financing programs under which products of the Borrower and/or its
Subsidiaries are sold to third party financing institutions which lease such
products to such customers, provided that the aggregate amount of all such
guaranties described in this Section 8.04(m) outstanding at any time shall not
exceed $25,000,000;"

          4.  In order to induce the Banks to enter into this Amendment, each of
Holdings and the Borrower hereby represents and warrants that (i) the
representations, warranties and agreements contained in Section 6 of the Credit
Agreement are true and correct in all material respects on the Fourth Amendment
Effective Date (as defined in Section 8 of this

                                       1
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Amendment after giving effect thereto) both before and after giving effect to
the Amendment with the same effect as though such representations and warranties
had been made on and as of the Fourth Amendment Effective Date (it being
understood and agreed that any representation or warranty which by its terms is
made as of a specified date shall be required to be true and correct in all
material respects only as of such specified date) and (ii) there exists no
Default or Event of Default on the Fourth Amendment Effective Date, both before
and after giving effect to this Amendment.

          5.  This Amendment is limited as specified and shall not constitute a
modification, acceptance or waiver of any other provision of the Credit
Agreement or any other Credit Document.

          6.  This Amendment may be executed in any number of counterparts and
by the different parties hereto on separate counterparts, each of which
counterparts when executed and delivered shall be an original, but all of which
shall together constitute one and the same instrument.  A complete set of
counterparts shall be lodged with the Borrower and the  Agent.

          7.  THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES
HEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAW OF THE
STATE OF NEW YORK.

          8.  This Amendment shall become effective on the date (the "Fourth
Amendment Effective Date") when each of Holdings, the Borrower and the Required
Banks shall have signed a counterpart hereof (whether the same or different
counterparts) and shall have delivered (including by way of facsimile
transmission) the same to the Agent at its address for notice provided for in
the Credit Agreement;

                                *      *      *

          IN WITNESS WHEREOF, each of the parties hereto has caused a
counterpart of this Amendment to be duly executed and delivered as of the date
first above written.

                                 WATERS CORPORATION

                                 By: /s/ Philip S. Taymor
                                    ---------------------------
                                 Title: Senior Vice President, Finance and
                                        Administration and Chief Financial
                                        Officer

                                       2
<PAGE>

                                    WATERS TECHNOLOGIES CORPORATION

                                    By: /s/ Philip S. Taymor
                                       -----------------------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    WATERS FRANCE HOLDING CORP.

                                    By: /s/ Philip S. Taymor
                                       -----------------------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    WATERS INVESTMENTS LIMITED

                                    By: /s/ Philip S. Taymor
                                       -----------------------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    NIHON WATERS LIMITED

                                    By: /s/ Philip S. Taymor
                                       -----------------------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                       3
<PAGE>

                                    WFE HOLDING, INC.

                                    By: /s/ Philip S. Taymor
                                       ---------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    WATERS ASIA LIMITED

                                    By: /s/ Philip S. Taymor
                                       ---------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    WATERS OPERATING CORP.

                                    By: /s/ Philip S. Taymor
                                       ---------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    T.A. INSTRUMENTS, INC.

                                    By: /s/ Philip S. Taymor
                                       ---------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                       4
<PAGE>

                                    WATERS OPERATING COMPANY, L.L.C.

                                    By: /s/ Philip S. Taymor
                                       ---------------------------
                                       Title: Senior Vice President, Finance and
                                              Administration and Chief Financial
                                              Officer

                                    BANKERS TRUST COMPANY,
                                    Individually, as Agent
                                    and as Collateral Agent

                                    By: /s/ Bankers Trust Company
                                       ---------------------------
                                       Title:

                                    FLEET BANK, N.A.

                                    By: /s/ Fleet Bank, N.A.
                                       ---------------------------
                                       Title:

                                    CREDIT INDUSTRIEL ET COMMERCIAL

                                    By:
                                       ---------------------------
                                       Title:

                                       5
<PAGE>

                                    ABN AMRO BANK N.V.

                                    By:/s/ ABN Amro Bank N.V.
                                       ---------------------------

                                    THE BANK OF NEW YORK

                                    By:
                                       ---------------------------
                                       Title:

                                    THE BANK OF NOVA SCOTIA

                                    By:
                                       ---------------------------
                                       Title:

                                    BANK OF SCOTLAND

                                    By:/s/ Bank of Scotland
                                       ---------------------------

                                       6
<PAGE>

                                    THE BANK OF TOKYO-MITSUBISHI TRUST COMPANY

                                    By:
                                       ---------------------------
                                       Title:

                                    CREDIT AGRICOLE INDOSUEZ

                                    By:
                                       ---------------------------
                                       Title:

                                    THE SAKURA BANK, LIMITED,
                                    NEW YORK BRANCH

                                    By:
                                       ---------------------------
                                       Title:

                                    WACHOVIA BANK, N.A.

                                    By:/s/ Wachovia Bank, N.A.
                                       ---------------------------

                                       7
<PAGE>

                                    FUJI BANK, LIMITED

                                    By:
                                       -----------------------------------------
                                       Title:

                                    GENERAL ELECTRIC CAPITAL CORPORATION

                                    By:/s/ General Electric Capital Corporation
                                       -----------------------------------------

                                    THE INDUSTRIAL BANK OF JAPAN

                                    By:
                                       -----------------------------------------
                                       Title:

                                    MELLON BANK, N.A.

                                    By:/s/ Mellon Bank, N.A.
                                       -----------------------------------------

                                       8
<PAGE>

                                    THE CHUO MITSUI TRUST & BANKING CO., LTD.

                                    By:
                                       ---------------------------
                                       Title:

                                    ALLIED IRISH BANKS, P.L.C.,
                                    NEW YORK BRANCH

                                    By:
                                       ---------------------------
                                       Title:

                                    CITIZENS BANK OF MASSACHUSETTS

                                    By:
                                       ---------------------------
                                       Title:

                                    THE ROYAL BANK OF SCOTLAND,
                                    PLC.

                                    By:
                                       ---------------------------
                                       Title:

                                    USTRUST

                                    By:
                                       ---------------------------
                                       Title:

                                       9<PAGE>

                                                                   Exhibit 10.43

                   THIRD AMENDMENT TO THE WATERS CORPORATION
                       1996 EMPLOYEE STOCK PURCHASE PLAN

          WHEREAS, Waters Corporation (the "Company") has established and
maintains a stock purchase plan for the benefit of employees of the Company
entitled the Waters Corporation 1996 Employee Stock Purchase Plan (the "Plan").

          WHEREAS, the Company has paid a stock dividend effective as of June
10, 1999 ("Stock Dividend"), in the amount of one share of Common Stock for each
share of Common Stock issued and outstanding and held of record as of May 27,
1999, in connection with which Stock Dividend and pursuant to the Plan, the
Company has authorized that the aggregate number of shares of the Common Stock
that may be issued under the Plan be doubled.

          WHEREAS, as of June 10, 1999, a total of 198,216 shares of the
Company's Common Stock were reserved for issuance pursuant to the Plan, and that
as a result of the Stock Dividend, such number of shares reserved for issuance
was doubled to 396,432 shares.

     NOW, THEREFORE, in accordance with the power of amendment contained in
Section 20 of the Plan, the Company having heretofore taken all necessary action
to amend the Plan, the Plan is hereby amended, as follows:

     1.   Section 3 is hereby amended by (a)  replacing the number "250,000" in
          the second line of the first sentence thereof with the number
          "500,000" and (b) adding the words "occurring after June 10, 1999"
          after the words "subject to adjustment" on the second line of Section
          3.

     2.   Section 10 is hereby amended by replacing the number "250,000" that
          appears on lines nine (9), eleven (11) and thirteen (13) of the single
          paragraph comprising Section 10, in each case, with the number
          "500,000."

     IN WITNESS WHEREOF, the Company has caused this amendment to be signed on
its behalf by its duly authorized representative this 10th day of June 1999.

                                          WATERS CORPORATION

                                          By:   /s/ Brian K. Mazar
                                              ---------------------------
                                                Brian K. Mazar
                                          Its:  Sr. VP, Human Resources
                                              ---------------------------

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