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                                                 Exhibit 4.1.1


                                                   EXECUTION COPY

               AMENDMENT NO. 1 TO CREDIT AGREEMENT


     This Amendment No. 1 (this "Amendment") is entered into as
of January 31, 2000 by and among BIO-RAD LABORATORIES, INC., a
Delaware corporation (the "Borrower"), the undersigned lenders
(collectively, the "Lenders") and BANK ONE, NA, having its
principal office in Chicago, Illinois, as one of the Lenders and
in its capacity as contractual representative (the "Agent") on
behalf of itself and the other Lenders.

                            RECITALS:

     WHEREAS, the Borrower, the Lenders and the Agent have
entered into that certain Credit Agreement dated as of September
30, 1999  (the "Credit Agreement");

     WHEREAS, the Borrower seeks to amend the Credit Agreement to
permit the refinancing of the Bridge Loan (as defined in the
Credit Agreement); and

     WHEREAS, the Lenders and the Agent are willing to amend the
Credit Agreement on the terms and conditions herein set forth;

     NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the
parties hereto hereby agree as follows:

     1.   Defined Terms.  Capitalized terms used herein and not
otherwise defined herein shall have the meanings attributed to
such terms in the Credit Agreement.

     2.   Amendments to Credit Agreement. Upon the effectiveness
of this Amendment in accordance with the provisions of Section 4
below, the Credit Agreement is hereby amended as follows:

     (a)  Article I of the Credit Agreement is amended by adding
   thereto the following new definitions:

          "New Bridge Loan" means the bridge loan in the initial
     principal amount of $100,000,000 made to the Borrower on or
     about January 31, 2000 pursuant to the New Bridge Loan
     Agreement to refinance the Bridge Loan in its entirety,
     including any increase in such principal amount as a result
     of the capitalization of interest thereon and including any
     Rollover Bridge Notes and Exchange Notes, as defined in the
     New Bridge Loan Agreement; provided that the Exchange Notes
     shall be issued pursuant to an indenture all of the terms
     and conditions of which are reasonably acceptable to the
     Agent and the Required Lenders, and provided further that
     terms and conditions substantially

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     similar to those contained in the Description of Notes shall
     be deemed to be reasonably acceptable.

         "New Bridge Loan Agreement" means the Senior
     Subordinated Credit Agreement dated as of January 31, 2000
     among the Borrower, the lenders named therein and UBS AG,
     Stamford Branch, as agent for such lenders, together with
     any notes issued pursuant thereto.

     (b)  Article I of the Credit Agreement is further amended by
     amending and restating in their entirety the following
     definitions as follows:

          "Consolidated EBITDA" means, with reference to any
     period, Consolidated Net Income for such period  plus, to
     the extent deducted from revenues in determining
     Consolidated Net Income (without duplication), (i)
     Consolidated Interest Expense and all non-cash interest
     expense, (ii) expense for income taxes paid or accrued,
     (iii) depreciation, (iv) amortization, (v) extraordinary
     losses incurred other than in the ordinary course of
     business and losses from discontinued operations, (vi) any
     extraordinary, unusual or non-recurring non-cash expenses or
     non-cash losses, and (vii) non-recurring cash charges,
     including any capitalized non-recurring cash charges, taken
     on or prior to March 31, 2000 resulting from severance,
     integration and other adjustments made as a result of the
     PSD Acquisition (provided that the amounts referred to in
     this clause (vii) shall not, in the aggregate, exceed
     $25,000,000), and minus, to the extent included in
     Consolidated Net Income, extraordinary gains and gains from
     discontinued operations, all net of tax, realized other than
     in the ordinary course of business, all calculated for the
     Borrower and its Subsidiaries on a consolidated basis for
     such period; provided that the items to be added to and
     subtracted from Consolidated Net Income with respect to any
     Subsidiary shall be added or subtracted only to the extent
     and in the same proportions that (a) the net income of such
     Subsidiary was included in the calculation of Consolidated
     Net Income, if such Subsidiary is not a Wholly-Owned
     Subsidiary and (b) the Consolidated EBITDA of such
     Subsidiary (calculated as if such Subsidiary were the
     "Borrower") is permitted to be paid or distributed as a
     dividend, advance, loan or other distribution to the
     Borrower.

          "Consolidated Net Income" means, with reference to any
     period, the net income (or loss) of the Borrower and its
     Subsidiaries calculated on a consolidated basis for such
     period, provided that Consolidated Net Income shall exclude
     the net income, if positive, of any of the Borrower's
     consolidated Subsidiaries to the extent that the declaration
     or payment of dividends of similar distributions is not at
     the time permitted by operation of the terms of its charter
     or by-laws or any other agreement, instrument, judgment,
     decree, order, statute, rule or governmental regulation
     applicable to such Subsidiary.

          "Description of Notes" means the Description of Notes
     attached hereto as Exhibit D, provided that the amount "$155
     million" in clause (3) of the description of "Limitation on
     Incurrence of Additional Indebtedness and Disqualified
     Capital Stock" in such Description

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     of Notes shall be deleted
     and the amount "$180 million" substituted therefor.

          "Financing" means, with respect to any Person, the
     issuance or sale by such Person of any Equity Interests of
     such Person or any Indebtedness consisting of debt
     securities of such Person pursuant to a registered offering
     or private placement, but excluding the issuance or sale of
     (i) any Indebtedness permitted to be incurred pursuant to
     Section 6.11, including, without limitation, the
     Subordinated Indebtedness, except that the first $20,000,000
     of Permitted Subordinated Indebtedness incurred in excess of
     the amount required to refinance the New Bridge Loan shall
     be deemed to be a Financing, (ii) Equity Interests by the
     Borrower to the extent that the proceeds thereof are used to
     refinance the New Bridge Loan in its entirety, (iii) Equity
     Interests by the Borrower to any officer, director or
     employee of the Borrower or any of its Subsidiaries pursuant
     to any incentive compensation plan or program and (iv)
     Equity Interests or Indebtedness by any Subsidiary of the
     Borrower to the Borrower or any Wholly-Owned Subsidiary of
     the Borrower.

          "Permitted Subordinated Indebtedness" means
     Indebtedness of the Borrower, the payment of which is
     subordinated to payment of the Secured Obligations and all
     of the terms and conditions of which are reasonably
     acceptable to the Agent and the Required Lenders, issued in
     an aggregate principal amount not to exceed $150,000,000,
     the proceeds of which are used, in whole or in part, to
     refinance the New Bridge Loan in its entirety; provided that
     terms and conditions substantially similar to those
     contained in the Description of Notes shall be deemed to be
     reasonably acceptable.

          "Subordinated Indebtedness" means the Bridge Loan, the
     New Bridge Loan and the Permitted Subordinated Indebtedness.

     (c)  Section 6.1 of the Credit Agreement is amended by
     deleting the figure "100" in Section 6.1(i) and substituting
     the figure "90" therefor, by deleting the figure "60" in
     Section 6.1(ii) and substituting the figure "45" therefor,
     and by deleting the phrase "Together with the financial
     statements required under Sections 6.1(i) and (ii)," in
     Section 6.1(iv) and substituting the following phrase
     therefor:

     Within 10 days after the delivery of the financial
     statements required under Section 6.1(i) and within 15 days
     after the delivery of the financial statements required
     under Section 6.1(ii),

     (d)  Section 6.21 of the Credit Agreement is amended by
     deleting the term "Bridge Loan Agreement" both places it
     appears in clause (i) thereof and substituting the term "New
     Bridge Loan Agreement" therefor and by deleting the term
     "Bridge Loan" in clause (ii) thereof and substituting the
     term "New Bridge Loan" therefor.

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     (e)  Section 6.22 of the Credit Agreement is amended by
     adding to the last sentence thereof after the phrase "the
     Bridge Loan" the phrase "and the New Bridge Loan".

     (f)  Section 7.5 of the Credit Agreement is amended by
     amending and restating the parenthetical phrase in the third
     clause thereof in its entirety to read as follows:

     (other than by a regularly scheduled payment and other than
     in connection with the refinancing of the Bridge Loan with
     the proceeds of the New Bridge Loan and the refinancing of
     the New Bridge Loan with the proceeds of Permitted
     Subordinated Indebtedness or Equity Interests of the
     Borrower)

     (g)  The Credit Agreement is amended by adding a new Exhibit
     D thereto in the form of Exhibit D attached to this
     Amendment.

     3.   Consent.  The Lenders hereby consent to the terms of
the Senior Subordinated Credit Agreement dated as of January 31,
2000 among the Borrower, the lenders named therein and UBS AG,
Stamford Branch, as agent for such lenders (the "New Bridge Loan
Agreement"), provided that such terms are substantially the same
as those contained in the draft dated January 26, 2000 (12:50
P.M.) of such Senior Subordinated Credit Agreement furnished to
the Lenders, and consent to the refinancing of the Bridge Loan
with the proceeds of the loans made pursuant to the New Bridge
Loan Agreement.

     4.   Conditions of Effectiveness.  This Amendment shall
become effective and be deemed effective as of the date hereof
(the "Effective Date") if, and only if, the Agent shall have
received duly executed originals of this Amendment from the
Borrower and the Required Lenders.

     5.   Representations and Warranties of the Borrower.  The
Borrower represents and warrants to the Lenders that, as of the
Effective Date:

          (a)  there exists no Default or Unmatured Default; and

          (b)  the representations and warranties contained in
     Article V of the Credit Agreement are true and correct as of
     the Effective Date except to the extent any such
     representation or warranty is stated to relate solely to an
     earlier date, in which case such representation or warranty
     was true and correct on and as of such earlier date.

     6.   Reference to and Effect on the Credit Agreement.

     6.1  Upon the effectiveness of this Amendment pursuant to
Section 4 hereof, on and after the Effective Date each reference
in the Credit Agreement to "this Agreement," "hereunder,"

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"hereof," "herein" or words of like import and each reference to
the Credit Agreement in each Loan Document shall mean and be a
reference to the Credit Agreement as modified hereby.

     6.2  Except as specifically waived or amended herein, all of
the terms, conditions and covenants of the Credit Agreement and
the other Loan Documents shall remain in full force and effect
and are hereby ratified and confirmed.

     6.3  The execution, delivery and effectiveness of this
Amendment shall not, except as expressly provided herein, operate
as a waiver of (a) any right, power or remedy of any Lender or
the Agent under the Credit Agreement or any of the Loan
Documents, or (b) any Default or Unmatured Default under the
Credit Agreement.

     7.   CHOICE OF LAW.  THIS AMENDMENT SHALL BE CONSTRUED IN
ACCORDANCE WITH THE INTERNAL LAWS (INCLUDING 735 ILCS 105/5-1 ET
SEQ. BUT OTHERWISE WITHOUT REGARD TO THE CONFLICT OF LAWS
PROVISIONS) OF THE STATE OF ILLINOIS, BUT GIVING EFFECT TO
FEDERAL LAWS APPLICABLE TO NATIONAL BANKS.

     8.   Counterparts.  This Amendment may be executed in any
number of counterparts, each of which when so executed shall be
deemed an original and all of which taken together shall
constitute one and the same agreement.

     9.   Headings.  Section headings in this Amendment are
included herein for convenience of reference only and shall not
constitute a part of this Amendment for any other purpose.

                    [Signature Pages Follow]

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     IN WITNESS WHEREOF, the Borrower, the Agent and the Lenders
have executed this Amendment No. 1 as of the date first above
written.


                         BIO-RAD LABORATORIES, INC.


                         By: /s/ Ronald W. Hutton
                               Name: Ronald W. Hutton
                               Title:  Treasurer


                         BANK ONE, NA, as a Lender and as Agent


                         By: /s/ Kandis A. Jaffrey
                               Name:  Kandis A. Jaffrey
                               Title: Vice President


                         ABN AMRO BANK N.V., as a Lender


                         By: /s/ Amanda C. Cox
                                Name:  Amanda C. Cox
                                Title: Vice President


                         By: /s/ Gina M. Brusatori
                                Name:  Gina M. Brusatori
                                Title: Group Vice President


                         UNION BANK OF CALIFORNIA, N.A.,
                           as a Lender


                         By: /s/ Michael E. Cooper
                              Name:  Michael E. Cooper
                              Title: Vice President

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                         THE BANK OF NOVA SCOTIA, as a Lender


                         By: /s/ M. Van Otterloo
                               Name:  M. Van Otterloo
                               Title: Managing Director, Corporate


                         BANQUE NATIONALE DE PARIS,
                            as a Lender


                         By: /s/ Debra Wright
                              Name: Debra Wright
                              Title:Vice President

                         By: /s/ Sandra Bertram
                               Name: Sandra Bertram
                               Title:Assistant Vice President


                         COOPERATIEVE CENTRALE RAIFFEISEN-
                           BOERENLEENBANK B.A., "RABOBANK
                           INTERNATIONAL",  NEW YORK BRANCH,
                           as a Lender


                         By:_________________________________
                              Name:
                              Title:

                         By:_________________________________
                               Name:
                               Title:


                         WELLS FARGO BANK,
                           as a Lender


                         By: /s/ Brian S. O'Melveny
                               Name:  Brian S. O'Melveny
                               Title: Vice President

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                         COMERICA BANK-CALIFORNIA,
                            as a Lender


                         By: /s/ R. Michael Law
                              Name:  R. Michael Law
                              Title: Vice President


                         CREDIT LYONNAIS NEW YORK BRANCH,
                           as a Lender


                         By: /s/ Robert Ivosevich
                               Name:  Robert Ivosevich
                               Title: Senior Vice President


                         LLOYDS TSB BANK PLC, as a Lender


                         By:/s/ Ian Dimmock
                              Name:  Ian Dimmock
                              Title: Vice President

                         By: /s/ Daivd Rodway
                               Name:  David Rodway
                               Title: Assistant Director


                         THE NORTHERN TRUST COMPANY,
                           as a Lender


                         By: /s/ Candelario Martinez
                              Name:  Candelario Martinez
                              Title: Vice President

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                         U.S. BANK, NATIONAL ASSOCIATION,
                           as a Lender


                         By: /s/ Meredith N. Davis
                              Name: Meredith N. Davis
                              Title:Assistant Vice President