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                                                                     EXHIBIT 4.3

                               SECURITY AGREEMENT

                          Dated as of September 9, 2003

                                     between

                           BIO-RAD LABORATORIES, INC.

                                   as Grantor

                                       and

                                  BANK ONE, NA,

                             as Administrative Agent

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                             EXHIBITS AND SCHEDULES

                                    Exhibits

EXHIBIT A    -- Form of Restricted Account Agreement

                                   Schedules

Schedule 1   -- Grantor Organizational Information

Schedule 1-A -- Pledged Debt

Schedule 2   -- Locations of Collateral

Schedule 2-A -- Third Party Locations

Schedule 2-B -- Financing Statement Filing Locations

Schedule 2-C -- Commercial Tort Claims

Schedule 3   -- Trade Names

Schedule 4   -- Deposit Accounts

Schedule 5   -- Federal Taxpayer Identification Number

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                               SECURITY AGREEMENT

          This SECURITY AGREEMENT ("Agreement"), dated as of September 9, 2003
is made by BIO-RAD LABORATORIES, INC., a Delaware corporation (together with its
successors and assigns, the "Grantor"), in favor of BANK ONE, NA (MAIN OFFICE
CHICAGO) (the "Administrative Agent"), for its benefit and for the benefit of
the "Holders of Secured Obligations" (as defined in the Credit Agreement
referred to below).

                             PRELIMINARY STATEMENTS

          WHEREAS, Grantor has entered into a certain Credit Agreement of even
date herewith among Grantor, the institutions from time to time parties thereto
as lenders (the "Lenders") and the Administrative Agent as the contractual
representative for the Lenders (as the same may be amended, restated,
supplemented or otherwise modified from time to time, the "Credit Agreement"),
providing for the making of loans, advances and other financial accommodations
(including, without limitation, letters of credit) (all such loans, advances and
other financial accommodations being hereinafter referred to collectively as the
"Loans") to or for the benefit of Grantor;

          WHEREAS, It is a condition precedent to the making of the Loans under
the Credit Agreement that Grantor shall have granted the security interest
contemplated by this Agreement; and

          WHEREAS, the Grantor wishes to secure the Secured Obligations owing to
the Holders of Secured Obligations pursuant to the terms of this Agreement;

          NOW, THEREFORE, in consideration of the premises set forth herein and
for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto agree as follows:

          SECTION 1. Defined Terms. Unless otherwise defined herein, terms
defined in the Credit Agreement are used herein as therein defined, and the
following terms shall have the following meanings (such meanings being equally
applicable to both the singular and the plural forms of the terms defined):

          "Agreement" shall mean this Security Agreement, as the same may from
time to time be amended, restated, modified or supplemented, and shall refer to
this Agreement as the same may be in effect at the time such reference becomes
operative.

          "Collateral" shall mean all property and interests in property now
owned or hereafter at any time acquired by Grantor in or upon which a Lien is
granted by Grantor in favor of the Administrative Agent for the benefit of the
Holders of Secured Obligations under this Agreement, including, without
limitation, the property described in Section 2.

          "Proceeds" shall mean whatever is receivable or received from or upon
the sale, lease, license, collection, use, exchange or other disposition,
whether voluntary or involuntary, of any Collateral, including "proceeds" as
defined in Section 9-102(64) of the UCC, any and all proceeds of any insurance,
indemnity, warranty or guaranty payable to or for the account of the Grantor
from time to time with respect to any of the Collateral, any and all payments
(in any

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form whatsoever) made or due and payable to Grantor from time to time in
connection with any requisition, confiscation, condemnation, seizure or
forfeiture of all or any part of the Collateral by any Governmental Authority
(or any Person acting under color of Governmental Authority), any and all other
amounts from time to time paid or payable under or in connection with any of the
Collateral or for or on account of any damage or injury to or conversion of any
Collateral by any Person, any and all other tangible or intangible property
received upon the sale or disposition of Collateral, and all proceeds of
proceeds.

          "Restricted Account" shall mean any deposit account listed on Schedule
4 hereof (i) that is maintained with Bank One, NA (Main Office Chicago), in its
capacity as Administrative Agent or otherwise, or (ii) with respect to which the
Grantor has entered into a Restricted Account Agreement substantially in the
form of Exhibit A hereto with the financial institution at which such deposit
account is maintained.

          "UCC" shall mean the Uniform Commercial Code as the same may, from
time to time, be in effect in the State of Illinois, as amended or supplemented
from time to time; provided, however, in the event that, by reason of mandatory
provisions of law, any or all of the attachment, perfection or priority of the
Administrative Agent's and the Holders of Secured Obligations' security interest
in any Collateral is governed by the Uniform Commercial Code as in effect in a
jurisdiction other than the State of Illinois, the term "UCC" shall mean the
Uniform Commercial Code as in effect in such other jurisdiction for purposes of
the provisions hereof relating to such attachment, perfection or priority and
for purposes of definitions related to such provisions. Any and all terms used
in this Agreement which are defined in the UCC shall be construed and defined in
accordance with the meaning and definition ascribed to such terms under the UCC,
unless otherwise defined herein.

          SECTION 2. Grant of Security. To secure the prompt and complete
payment, observance and performance of the Secured Obligations, Grantor hereby
collaterally assigns and pledges to Administrative Agent, for the benefit of
Administrative Agent and the Holders of Secured Obligations, and hereby grants
to Administrative Agent, for the benefit of Administrative Agent and the Holders
of Secured Obligations, a security interest in all of Grantor's right, title and
interest in and to the following, whether now owned or existing or hereafter
arising or acquired and wheresoever located and Proceeds thereof:

          ACCOUNTS: All "accounts" as such term is defined in Section 9-102(2)
of the UCC, whether now owned or hereafter acquired or arising; Grantor intends
that the term "accounts", as used herein, be construed in its broadest sense,
and such term shall include, without limitation, all present and future
accounts, accounts receivable (including, without limitation,
health-care-insurance receivables, and all other forms of monetary obligations
owing to Grantor, and all credit insurance, guaranties, or security therefor,
but excluding those items evidenced by instruments or chattel paper), whether
now existing or hereafter arising and wherever arising, and whether or not they
have been earned by performance (collectively, "Accounts");

          INVENTORY: All "inventory" as such term is defined in Section
9-102(48) of the UCC, whether now owned or hereafter acquired or arising;
Grantor intends that the term "inventory", as used herein, be construed in its
broadest sense, and such term shall include, without limitation, all goods now
owned or hereafter acquired by Grantor (wherever located,

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whether in the possession of Grantor or of a bailee or other person for sale,
storage, transit, processing, use or otherwise and whether consisting of whole
goods, spare parts, components, supplies, materials, or consigned, returned or
repossessed goods) which are held for sale or lease, which are to be furnished
(or have been furnished) under any contract of service or which are raw
materials, work in process or materials used or consumed in Grantor's business
(collectively, "Inventory");

          EQUIPMENT: All "equipment" as such term is defined in Section
9-102(33) of the UCC, whether now owned or hereafter acquired or arising;
Grantor intends that the term "equipment", as used herein, be construed in its
broadest sense, and such term shall include, without limitation, all machinery,
all manufacturing, distribution, selling, data processing and office equipment,
all furniture, furnishings, appliances, fixtures and trade fixtures, tools,
tooling, molds, dies, vessels, rolling stock, motor vehicles and all other goods
(including software embedded in such goods) of every type and description (other
than Inventory), in each instance whether now owned or hereafter acquired by
Grantor and wherever located (collectively, "Equipment");

          GENERAL INTANGIBLES: All "general intangibles" (including payment
intangibles) as such term is defined in Section 9-102(42) of the UCC, whether
now owned or hereafter acquired or arising; Grantor intends that the term
"general intangibles", as used herein, be construed in its broadest sense, and
such term shall include, without limitation, the uniform resource locator
*www.bio-rad.com**, all rights, interests, choses in action, causes of action,
claims and all other intangible property of Grantor of every kind and nature
(other than Accounts), in each instance whether now owned or hereafter acquired
by Grantor and however and whenever arising, including, without limitation, all
corporate and other business records; all loans, royalties, and other
obligations receivable; customer lists, credit files, correspondence, and
advertising materials; all firm sale orders, other contracts and contract
rights; all interests in partnerships, limited liability companies and joint
ventures; all tax refunds and tax refund claims; all right, title and interest
under leases, subleases, licenses and concessions and other agreements relating
to real or personal property; all payments due or made to Grantor in connection
with any requisition, confiscation, condemnation, seizure or forfeiture of any
property by any person or governmental authority; all payments due or made to
the Grantor in connection with any choses in action, causes of action or other
claims; all credits with and other claims against carriers and shippers; all
rights to indemnification; all patents, and patent applications (including all
reissues, divisions, continuations and extensions) (collectively, "Patents");
all trade secrets and inventions; all copyrights and copyright applications
(including all computer software and related documentation) (collectively,
"Copyrights"); all service marks and service mark applications and all rights
and interests in and to trademarks, trademark registrations and applications
therefor, trade names, corporate names, brand names, slogans, and all goodwill
associated with the foregoing (collectively, "Trademarks", and together with
Copyrights and Patents, "Intellectual Property"); all license agreements and
franchise agreements, all reversionary interests in pension and profit sharing
plans and reversionary, beneficial and residual interest in trusts; all proceeds
of insurance of which Grantor is beneficiary; and all letters of credit,
guaranties, liens, security interests and other security held by or granted to
Grantor; and all other intangible property, whether or not similar to the
foregoing;

          LAB PROCESSING AND ENGINEERING INFORMATION: All rights and interests
in and to processes, lab journals, and notebooks, data, trade secrets, know-how,
product

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formulae and information, manufacturing, engineering and other drawings and
manuals, technology, blueprints, research and development reports, agency
agreements, technical information, technical assistance, engineering data,
design and engineering specifications, and similar materials recording or
evidencing expertise used in or employed by Grantor (including any license for
the foregoing), in each case whether now owned or hereafter acquired or arising;

          CONTRACT RIGHTS: All rights and interests in and to any pending or
executory contracts, requests for quotations, invitations for bid, agreements,
leases and arrangements of which Grantor is a party to or in which Grantor has
an interest;

          CHATTEL PAPER, INSTRUMENTS AND DOCUMENTS: All chattel paper (including
tangible chattel paper, intangible chattel paper and electronic chattel paper),
leases, all instruments, including, without limitation, the notes and debt
instruments described in Schedule 1-A (the "Pledged Debt") and all payments
thereunder and instruments and other property from time to time delivered in
respect thereof or in exchange therefor, and all bills of sale, bills of lading,
warehouse receipts and other documents of title, whether or not negotiable, and
includes all other documents which purport to be issued by a bailee or agent and
purport to cover goods in any bailee's or agent's possession which are either
identified or are fungible portions of an identified mass, including such
documents of title made available to Administrative Agent for the purpose of
ultimate sale or exchange of goods or for the purpose of loading, unloading,
storing, shipping, transshipping, manufacturing, processing or otherwise dealing
with goods in a manner preliminary to their sale or exchange, in each instance
whether now owned or hereafter acquired by Grantor;

          INTEREST AND CURRENCY CONTRACTS: Any and all interest rate, commodity
or currency exchange agreements or derivative agreements, including, without
limitation, cap, collar, floor, forward or similar agreements or other rate,
currency or price protection arrangements or hedging agreements;

          BOOKS AND RECORDS: All presently existing and hereafter acquired or
created books and records of Grantor, including all records (including
maintenance and warranty records), ledgers, computer programs and files, disc or
tape files, printouts, runs, and other computer prepared information indicating,
summarizing, or evidencing the Collateral;

          COMMERCIAL TORT CLAIMS: All rights and interests in and to any
commercial tort claims, which are listed on Schedule 2-C hereto or supplements
to this Agreement from time to time;

          DEPOSIT ACCOUNTS: All "deposit accounts" as such term is defined in
Section 9-102(29) of the UCC, whether now owned or hereafter acquired or
arising; Grantor intends that the terms "deposit accounts", as used herein, be
construed in its broadest sense, and such term shall include, without
limitation, all demand, time, savings, passbook or similar accounts now or
hereafter maintained by or for the benefit of Grantor with an organization that
is engaged in the business of banking including a bank, savings bank, savings
and loan association, credit union and trust companies, and all funds and
amounts therein, whether or not restricted or designated for a particular
purpose (collectively, "Deposit Accounts");

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          INVESTMENT PROPERTY: All "investment property" as such term is defined
in Section 9-102(49) of the UCC, whether now owned or hereafter acquired or
arising;

          LETTER-OF-CREDIT RIGHTS: All "letter-of-credit rights" as such term is
defined in Section 9-102(51) of the UCC, whether now owned or hereafter acquired
or arising;

          SUPPORTING OBLIGATIONS: All "supporting obligations" as such term is
defined in Section 9-102(77) of the UCC, in respect of any of the foregoing
property, whether now owned or hereafter acquired or arising; and

          OTHER PROPERTY: All property or interests in property now owned or
hereafter acquired by Grantor which now may be owned or hereafter may come
within the possession, custody or control of Administrative Agent or any of the
Holders of Secured Obligations or any agent or Affiliate of any of them in any
way and for any purpose (whether for safekeeping, custody, pledge, transmission,
collection or otherwise); and all rights and interests of Grantor, now existing
or hereafter arising and however and wherever arising, in respect of any and all
(i) money; (ii) proceeds of loans, including, without limitation, Loans made
under the Credit Agreement; and (iii) insurance proceeds and books and records
relating to any of the property covered by this Agreement; together, in each
instance, with all accessions and additions thereto, substitutions therefor, and
replacements, Proceeds and products thereof.

Notwithstanding the foregoing provisions of Section 2, such grant of security
interest shall not extend to, and the term "Collateral" shall not include, (i)
any general intangibles, lab processing and engineering information, contract
rights, chattel paper, instruments and documents which are now or hereafter held
by Grantor as licensee, lessee or otherwise, to the extent that (a) such general
intangibles, lab processing and engineering information, contract rights,
chattel paper, instruments or documents are not assignable or capable of being
encumbered as a matter of law or under the terms of the license, lease or other
agreement applicable thereto (but solely to the extent that any such restriction
shall be enforceable under applicable law), without the consent of the licensor
or lessor thereof or other applicable party thereto and (b) such consent has not
been obtained; provided, however, that the foregoing grant of security interest
shall extend to, and the term "Collateral" shall include, (1) any and all
proceeds of such general intangibles, lab processing and engineering
information, contract rights, chattel paper, instruments and documents to the
extent that the assignment or encumbering of such proceeds is not so restricted
and (2) upon any such licensor, lessor or other applicable party consent with
respect to any otherwise excluded general intangibles, lab processing and
engineering information, contract rights, chattel paper, instruments or
documents being obtained, thereafter such general intangibles, lab processing
and engineering information, contract rights, chattel paper, instruments or
documents as well as any and all proceeds thereof that might theretofore have
been excluded from such grant of a security interest and the term "Collateral";
or (ii) Equity Interests held by the Grantor in any of its Foreign Subsidiaries
until such grant is required pursuant to Section 6.28(b) of the Credit
Agreement, and any such security interest, individually or collectively, with
respect to any Foreign Subsidiary shall at no time exceed 65% of the Voting
Equity Interests of such Foreign Subsidiary, regardless of whether certificate
representing a greater percentage may be delivered to the Administrative Agent.

          SECTION 3. Authorization. Grantor hereby authorizes Administrative
Agent to retain and each Holder of Secured Obligations, and each Affiliate of
Administrative Agent and

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of each Holder of Secured Obligations, to pay or deliver to Administrative
Agent, for the benefit of the Holders of Secured Obligations, without any
necessity on the part of any Holder of Secured Obligations to resort to other
security or sources of reimbursement for the Secured Obligations, at any time
following the occurrence and during the continuance of any Default, and without
further notice to Grantor (such notice being expressly waived), any of the
deposits referred to in Section 2 (whether general or special, time or demand,
provisional or final, other than trust accounts) or other sums or property held
by such Person, for application against any portion of the Secured Obligations,
irrespective of whether any demand has been made or whether such portion of the
Secured Obligations is due and payable. Administrative Agent will promptly
notify Grantor of Administrative Agent's receipt of such funds or other property
for application against the Secured Obligations, but failure to do so will not
affect the validity or enforceability thereof. Administrative Agent may give
notice of the above authorization, grant of security interest and assignment of
the aforesaid deposits and other sums by Grantor to, and may make any suitable
arrangements with, any such Holder of Secured Obligations for effectuation
thereof, and Grantor hereby irrevocably appoints Administrative Agent as its
attorney to collect any and all such deposits or other sums to the extent any
such payment is not made to Administrative Agent by such Holder of Secured
Obligations or Affiliate thereof; provided, that the Administrative Agent agrees
not to exercise such powers as attorney-in-fact unless a Default has occurred
and is continuing.

          SECTION 4. Grantor Remains Liable. Anything herein to the contrary
notwithstanding, (a) Grantor shall remain solely liable under the contracts and
agreements included in the Collateral to the extent set forth therein to perform
all of its duties and obligations thereunder to the same extent as if this
Agreement had not been executed, (b) the exercise by Administrative Agent of any
of its rights hereunder shall not release Grantor from any of its duties or
obligations under the contracts and agreements included in the Collateral, and
(c) neither Administrative Agent nor the Holders of Secured Obligations shall
have any responsibility, obligation or liability under the contracts and
agreements included in the Collateral by reason of this Agreement, nor shall
Administrative Agent or the Holders of Secured Obligations be required or
obligated, in any manner, to (i) perform or fulfill any of the obligations or
duties of Grantor thereunder, (ii) make any payment, or make any inquiry as to
the nature or sufficiency of any payment received by Grantor or the sufficiency
of any performance by any party under any such contract or agreement or (iii)
present or file any claim, or take any action to collect or enforce any claim
for payment assigned hereunder.

          SECTION 5. Representations and Warranties. Grantor represents and
warrants, as of the date of this Agreement:

          (a) The exact legal name, jurisdiction of organization and
Organizational Identification Number of Grantor is set forth on Schedule 1 to
this Agreement, and Grantor's Federal Taxpayer Identification Number is set
forth on Schedule 5 hereto. Grantor is only organized in the jurisdiction set
forth in Schedule 1 to this Agreement and is not organized under the laws of any
other jurisdiction. The locations listed for Grantor on Schedule 2 hereto
constitute all locations at which Inventory and/or Equipment with a value in
excess of $1,000,000 is located and Grantor has exclusive possession and control
of such Equipment and Inventory, except for such Inventory and Equipment which
is (i) temporarily in transit between such locations, or (ii) temporarily stored
with third parties or held by third parties for processing, storage,
engineering, evaluation, repairs or sale, the proper corporate names of which
third

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parties, the location of such Inventory and/or Equipment, and the nature of the
relationship between Grantor and such third parties are set forth in Schedule
2-A. The chief place of business and chief executive office of Grantor are
located at the address of Grantor set forth below the Grantor's signature on the
Credit Agreement. All books and records concerning any Accounts and all
originals of all chattel paper are located at the addresses listed on Schedule 2
and none of the Accounts is evidenced by a promissory note or other instrument
in excess of $1,000,000 except for such notes and other instruments delivered to
Administrative Agent as Pledged Debt listed on Schedule 1-A.

          (b) Grantor is the legal and beneficial owner of the Collateral free
and clear of all Liens except for Liens permitted by Section 6.15 of the Credit
Agreement. Grantor conducts business under the name BIO-RAD LABORATORIES, INC.
and, in certain areas and for certain operations, the trade names listed on
Schedule 3. The Grantor uses no trade names or fictitious names, except as set
forth on Schedule 3.

          (c) This Agreement creates in favor of Administrative Agent a legal,
valid and enforceable security interest in the Collateral (other than Equipment
and Inventory located in a jurisdiction outside the United States of America).
When financing statements have been filed in the appropriate offices against
Grantor in the locations listed on Schedule 2-B and, with respect to any
intellectual property that shall constitute Collateral hereunder, any necessary
filings have been made with the U.S. Patent and Trademark Office and the U.S.
Copyright Office, Administrative Agent will have a fully perfected first
priority lien on, and security interest in, such Collateral in which a security
interest may be perfected by such filing, subject only to Liens permitted by
Section 6.15 of the Credit Agreement.

          (d) No authorization, approval or other action by, and no notice to or
filing with, any Governmental Authority, that has not already been taken or made
and that is in full force and effect, is required (a) for the grant by Grantor
of the security interest in the Collateral granted hereby; (b) for the
execution, delivery or performance of this Agreement by Grantor; or (c) for the
exercise by Administrative Agent of any of its rights or remedies hereunder,
except (x) filings, consents or notices which if not made, obtained or given,
individually and in the aggregate could not reasonably be expected to have a
Material Adverse Effect and (y) filings and other actions referred to in Section
5(c) hereof.

          (e) The Pledged Debt issued by any Affiliate of Grantor, and to the
best of Grantor's knowledge, all other Pledged Debt, has been duly authorized,
issued and delivered, and is the legal, valid, binding and enforceable
obligation of the respective issuer thereof.

          (f) Schedule 4 contains a complete list of all of the Deposit Accounts
of Grantor as of the Closing Date, and Grantor will amend and update Schedule 4
by delivering supplemental reports to Administrative Agent promptly following
the establishment of any additional Deposit Accounts, but in any event not less
frequently than on a calendar quarterly basis, and at any time requested by the
Administrative Agent. Except as indicated on Schedule 4, as of the date of this
Agreement, each Deposit Account so scheduled is a Restricted Account.

          SECTION 6. Perfection and Maintenance of Security Interests and Liens.
Grantor agrees that until all of the Secured Obligations (other than contingent
indemnity obligations) have been fully satisfied and the Credit Agreement has
been terminated,

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Administrative Agent's security interests in and Liens on and against the
Collateral and all proceeds and products thereof shall continue in full force
and effect. Grantor shall perform any and all steps reasonably requested by
Administrative Agent to perfect, maintain and protect Administrative Agent's
security interests in and Liens on and against the Collateral granted or
purported to be granted hereby or to enable Administrative Agent to exercise its
rights and remedies hereunder with respect to any Collateral; provided, however,
that the Grantor shall not be required to take any steps to perfect, maintain or
protect the Administrative Agent's security interest in any patents, copyrights,
trademarks or other intellectual property under applicable law in any
jurisdiction other than the United States of America, in money, in vehicles
covered by certificates of title, or, unless a Default shall have occurred and
be continuing, at the request of the Administrative Agent, in letter of credit
rights. The steps to be performed by the Grantor include, without limitation:

          (i) filing financing or continuation statements, or amendments
     thereof, in form and substance reasonably satisfactory to Administrative
     Agent;

          (ii) delivering to Administrative Agent all certificates, notes and
     other instruments with a value in excess of $1,000,000 (including, without
     limitation, all letters of credit on which Grantor is named as a
     beneficiary thereof) representing or evidencing Collateral, which
     certificates, notes and other instruments have been duly endorsed or are
     accompanied by duly executed instruments of transfer or assignment,
     including, but not limited to, note powers, all in form and substance
     satisfactory to Administrative Agent;

          (iii) at the reasonable direction of the Administrative Agent,
     delivering to Administrative Agent warehouse receipts covering that portion
     of the Collateral, if any, located in warehouses and for which warehouse
     receipts are issued;

          (iv) after the occurrence and during the continuance of a Default,
     transferring Inventory and Equipment to warehouses designated by
     Administrative Agent or taking such other steps as are reasonably deemed
     necessary by Administrative Agent to maintain Administrative Agent's
     control of the Inventory and Equipment;

          (v) at the reasonable direction of the Administrative Agent, marking
     conspicuously each instrument, document, contract, chattel paper (in each
     case with a value in excess of $1,000,000) and all books and records
     pertaining to the Collateral with a legend, in form and substance
     satisfactory to Administrative Agent, indicating that such instrument,
     document, contract, chattel paper, or Collateral is subject to the security
     interest granted hereby;

          (vi) when required by Section 6.30 of Credit Agreement, obtaining
     restricted account agreements in substantially the form of Exhibit A hereto
     (or such other form as may be agreed to by the Administrative Agent) (each
     a "Restricted Account Agreement") from banks with respect to all then
     existing Deposit Accounts (other than Deposit Accounts maintained with the
     Administrative Agent) in the name of any Grantor (in connection with which
     the Grantor shall be permitted to and is required to update Schedule 4), in
     excess of $100,000 individually and $1,000,000 in the aggregate;

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          (vii) at the reasonable request of the Administrative Agent, appearing
     in and defending any action or proceeding which may affect materially and
     adversely Grantor's title to, or the security interest of Administrative
     Agent in, any of the Collateral; and

          (viii) executing and delivering all further instruments and documents,
     and taking all further action, as Administrative Agent may reasonably
     request.

          SECTION 7. Financing Statements. To the extent permitted by applicable
law, Grantor hereby authorizes Administrative Agent to file one or more
financing or continuation statements and amendments thereto, disclosing the
security interest granted to Administrative Agent under this Agreement without
Grantor's signature appearing thereon, and Administrative Agent agrees to notify
Grantor when such a filing has been made. Grantor agrees that a carbon,
photographic, photostatic, or other reproduction of this Agreement or of a
financing statement is sufficient as a financing statement.

          SECTION 8. Filing Costs. Grantor shall pay the costs of, or incidental
to, all UCC, tax lien and judgment searches and all recordings or filings of all
financing statements, including, without limitation, any filing expenses
incurred by Administrative Agent pursuant to Section 7.

          SECTION 9. General Covenants. Grantor covenants and agrees with
Administrative Agent that from and after the date of this Agreement and until
termination of this Agreement pursuant to Section 20:

          (a) Grantor will comply with the terms of the Credit Agreement with
respect to such Equipment and Inventory, including, without limitation, the
maintenance and insurance provisions set forth in Sections 6.6 and 6.8 of the
Credit Agreement;

          (b) Grantor shall keep its jurisdiction of organization specified in
Section 5(a) or, upon thirty (30) days' prior written notice to Administrative
Agent, such other jurisdiction within the United States where all actions
required by Section 6 shall have been taken;

          (c) Grantor shall keep and maintain at Grantor's own cost and expense
satisfactory and complete records of Grantor's Collateral in a manner consistent
with Grantor's current business practice and, where applicable, Agreement
Accounting Principles, including, without limitation, a record of all payments
received and all credits granted with respect to such Collateral. Grantor shall,
for Administrative Agent's further security, deliver and turn over to
Administrative Agent or Administrative Agent's designated representatives at any
time following the occurrence and during the continuation of a Default, any such
books and records (including, without limitation, any and all computer tapes,
programs and files and any and all source and object codes relating to such
Collateral in which Grantor has an interest or any part or parts thereof);

          (d) Grantor will not create, permit or suffer to exist, and will
defend the Collateral against, and take such other action as is necessary to
remove, any Lien on such Collateral other than Liens permitted under Section
6.15 of the Credit Agreement, and will defend the right, title and interest of
Administrative Agent in and to Grantor's rights to such Collateral, including,
without limitation, the proceeds and products thereof, against the claims

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and demands of all Persons whatsoever, other than holders of Liens permitted
under Section 6.15 of the Credit Agreement;

          (e) Grantor will not (i) make any change to its name, organizational
structure or merge or consolidate with any other entity unless, at least thirty
(30) days prior to the effective date of any such change, Grantor notifies the
Administrative Agent and delivers thereto acknowledgment copies of such
financing statements which the Administrative Agent may reasonably request to
reflect such change, together with such other documents and instruments that the
Administrative Agent may reasonably request in connection therewith, and has
taken all other reasonable steps to ensure that the Administrative Agent, for
the benefit of the Holders of Secured Obligations, continues to have a first
priority, perfected ownership or security interest in all the Collateral owned
by Grantor, or (ii) change its jurisdiction of organization unless the
Administrative Agent shall have received from Grantor prior to such change those
items described in clause (i) hereof.

          (f) If Grantor shall at any time hold or acquire a commercial tort
claim with a value in excess of $1,000,000, Grantor shall promptly notify the
Administrative Agent of such commercial tort claim and shall grant to the
Administrative Agent on behalf of the Holders of Secured Obligations a security
interest in such commercial tort claim, together with all proceeds thereof. Such
security interest shall be granted by Grantor to the Administrative Agent in a
writing in form and substance acceptable to the Administrative Agent and shall
identify with specificity the applicable commercial tort claim.

          SECTION 10. Administrative Agent Appointed Attorney-in-Fact. Grantor
hereby irrevocably appoints Administrative Agent as Grantor's attorney-in-fact,
coupled with an interest, with full authority in the place and stead of Grantor
and in the name of Grantor or otherwise, from time to time in Administrative
Agent's discretion, following the occurrence and during the continuance of a
Default, to take any action and to execute any instrument which Administrative
Agent may reasonably deem necessary or advisable to accomplish the purposes of
this Agreement, including, without limitation, to:

          (i) obtain and adjust insurance required to be paid to the
     Administrative Agent or any Holders of Secured Obligations pursuant to the
     Loan Documents;

          (ii) ask, demand, collect, sue for, recover, compromise, receive and
     give acquittance and receipts for monies due and to become due under or in
     respect of any of the Collateral;

          (iii) receive, endorse, and collect any drafts or other instruments,
     documents and chattel paper, in connection with clause (i) or (ii) above;
     and

          (iv) file any claims or take any action or institute any proceedings
     which Administrative Agent may deem necessary or desirable for the
     collection of any of the Collateral, or otherwise to enforce the rights of
     Administrative Agent with respect to any of the Collateral.

                                       10

<PAGE>

          SECTION 11. Administrative Agent May Perform; Collection of Accounts.
If Grantor fails to perform any agreement contained herein or in the Credit
Agreement after the expiration of any applicable grace or cure periods,
Administrative Agent may, in accordance with Section 9.13 of the Credit
Agreement, perform, or cause performance of, such agreement, and the expenses of
Administrative Agent incurred in connection therewith shall constitute Secured
Obligations and shall be payable by Grantor under Section 17. Following the
occurrence and during the continuance of a Default, the Administrative Agent
shall have the right, with respect to Accounts that constitute part of the
Collateral, (i) to notify any account debtors (as defined in Section 9-102(3) of
the UCC) of Grantor to make payments directly to the Administrative Agent for
application to the Secured Obligations and (ii) to enforce Grantor's rights
against the applicable account debtors.

          SECTION 12. Administrative Agent's Duties. The powers conferred on
Administrative Agent hereunder are solely to protect its interest in the
Collateral and shall not impose any duty upon it to exercise any such powers.
Except for the safe custody of any Collateral in its possession and the
accounting for monies actually received by it hereunder, Administrative Agent
shall not have any duty as to any Collateral. Administrative Agent shall be
deemed to have exercised reasonable care in the custody and preservation of the
Collateral in its possession if the Collateral is accorded treatment
substantially equal to that which Administrative Agent accords its own property,
it being understood that Administrative Agent shall be under no obligation to
take any necessary steps to preserve rights against prior parties or any other
rights pertaining to any Collateral, but may do so at its option, and all
reasonable expenses incurred in connection therewith shall be for the sole
account of Grantor and shall be added to the Secured Obligations. Grantor bears
all risk of loss or damage of any of the Collateral, except to the extent such
loss or damage shall arise solely from the gross negligence or willful
misconduct of the Administrative Agent.

          SECTION 13. Remedies.

          (a) If any Default shall have occurred and be continuing:

          (i) Administrative Agent shall have, in addition to other rights and
     remedies provided for herein or otherwise available to it, all the rights
     and remedies of a secured party upon default under the UCC (whether or not
     the UCC applies to the affected Collateral) and further, Administrative
     Agent may, without notice, demand or legal process of any kind (except as
     may be required by law or specifically required under the Credit
     Agreement), all of which Grantor waives, at any time or times, (x)
     peacefully enter Grantor's owned or leased premises and take physical
     possession of the Collateral and maintain such possession on Grantor's
     owned or leased premises, at no cost to Administrative Agent or any of the
     Holders of Secured Obligations, or remove the Collateral, or any part
     thereof, to such other place(s) as Administrative Agent may desire, (y)
     require Grantor to, and Grantor hereby agrees that it will at its expense
     and upon request of Administrative Agent forthwith, assemble all or any
     part of the Collateral as directed by Administrative Agent and make it
     available to Administrative Agent at a place to be designated by
     Administrative Agent which is reasonably convenient to Administrative Agent
     and (z) without notice except as specified below or specifically required
     under the Credit Agreement, sell, lease, assign, grant an option or options
     to purchase or otherwise dispose of the Collateral or any part thereof at
     public or private

                                       11

<PAGE>

     sale, at any exchange, broker's board or at any of the offices of
     Administrative Agent or elsewhere, for cash, on credit or for future
     delivery, or upon such other terms as Administrative Agent may deem
     commercially reasonable. Grantor agrees that, to the extent notice of sale
     shall be required by law, at least ten (10) days' notice to Grantor of the
     time and place of any public sale or the time after which any private sale
     is to be made shall constitute reasonable notification. Administrative
     Agent shall not be obligated to make any sale of Collateral regardless of
     notice of sale having been given. Administrative Agent may adjourn any
     public or private sale from time to time by announcement at the time and
     place fixed therefor, and such sale may, without further notice, be made at
     the time and place to which it was so adjourned. Administrative Agent shall
     have no obligation to clean-up or otherwise prepare the Collateral for
     sale. It is not necessary that the Collateral be present at any such sale.

          (ii) Administrative Agent shall apply all cash proceeds received by
     Administrative Agent in respect of any sale of, collection from, or other
     realization upon all or any part of the Collateral (after payment of any
     amounts payable to Administrative Agent pursuant to Section 17), for the
     benefit of the Holders of Secured Obligations, against all or any part of
     the Secured Obligations in such order as may be required by the Loan
     Documents. Any surplus of such cash or cash proceeds held by Administrative
     Agent and remaining after payment in full of all the Secured Obligations
     shall be paid over to Grantor or to whomsoever may be lawfully entitled to
     receive such surplus (including, but not limited to, as a court of
     competent jurisdiction may otherwise direct).

          (b) Administrative Agent shall have no obligation to attempt to
satisfy the Secured Obligations by collecting them from any third Person which
may be liable for them or any portion thereof, and the Administrative Agent may
release, modify or waive any collateral provided by any other Person as security
for the Secured Obligations or any portion thereof, all without affecting the
Administrative Agent's rights against Grantor. Grantor waives any right it may
have to require any Holder of Secured Obligations to pursue any third Person for
any of the Secured Obligations.

          (c) Grantor waives, to the extent permitted by applicable law, all
claims, damages and demands against Administrative Agent arising out of the
repossession, retention or sale of any of the Collateral or any part or parts
thereof, except any such claims, damages and awards arising out of the gross
negligence or willful misconduct of Administrative Agent or any of the Holders
of Secured Obligations, or their respective officers, directors, agents,
affiliates or employees, as the case may be, as determined in a final,
non-appealable judgment of a court of competent jurisdiction.

          (d) The rights and remedies provided under this Agreement are
cumulative and may be exercised singly or concurrently and are not exclusive of
any rights and remedies provided by applicable law or equity.

          SECTION 14. Exercise of Remedies. In connection with the exercise of
its remedies pursuant to Section 13, Administrative Agent may, except as
restricted or prohibited by applicable law, (i) exchange, enforce, waive or
release any portion of the Collateral and any other security for the Secured
Obligations; (ii) apply such Collateral or security and direct the order or
manner of sale thereof as Administrative Agent may, from time to time,
determine; and

                                       12

<PAGE>

(iii) settle, compromise, collect or otherwise liquidate any such Collateral or
security in any manner following the occurrence of a Default, without affecting
or impairing Administrative Agent's right to take any other further action with
respect to any Collateral or security or any part thereof.

          SECTION 15. License. Administrative Agent is hereby granted a license
or other right to use, following the occurrence and during the continuance of a
Default and notice to Grantor, without charge, (a) Grantor's labels, patents,
copyrights, trade secrets, trade names, trademarks, service marks, customer
lists and advertising matter, or any property of a similar nature, as it
pertains to the Collateral, in completing production of, advertising for sale,
and/or selling any Collateral, provided that Administrative Agent uses quality
standards at least substantially equivalent to those of Grantor for the
manufacture, advertising, sale and distribution of Grantor's products and
services and (b) Grantor's rights under all licenses and all franchise
agreements shall inure to Administrative Agent's benefit, except to the extent
restricted or prohibited by the terms of such licenses or agreements.

          SECTION 16. Interpretation and Inconsistencies; Merger.

          (a) The rights and duties created by this Agreement shall, in all
cases, be interpreted consistently with, and shall be in addition to (and not in
lieu of), the rights and duties created by the Credit Agreement and the other
Loan Documents. In the event that any provision of this Agreement shall be
inconsistent with any provision of any other Loan Document, such provision of
the other Loan Document shall govern.

          (b) Except as provided in subsection (a) above, this Agreement
represents the final agreement of the Grantor and the Administrative Agent with
respect to the matters contained herein and may not be contradicted by evidence
of prior or contemporaneous agreements, or subsequent oral agreements, between
the Grantor and the Administrative Agent or any other Holder of Secured
Obligations.

          SECTION 17. Expenses. Grantor will pay to Administrative Agent and/or
the Holders of Secured Obligations the amount of any and all reasonable
expenses, including the reasonable fees and disbursements of their counsel and
of any experts and agents, as provided in Section 9.6 of the Credit Agreement.

          SECTION 18. Amendments, Etc. No amendment or waiver of any provision
of this Agreement nor consent to any departure by Grantor herefrom shall in any
event be effective unless the same shall be in writing and signed by
Administrative Agent and Grantor, and then such waiver or consent shall be
effective only in the specific instance and for the specific purpose for which
given.

          SECTION 19. Notices. All notices and other communications provided for
hereunder shall be delivered in the manner set forth in Section 13.1 of the
Credit Agreement.

          SECTION 20. Continuing Security Interest; Termination. (a) Except as
provided in Section 20(b), this Agreement shall create a continuing security
interest in the Collateral and shall (i) remain in full force and effect until
the later of the payment or satisfaction in full of the Secured Obligations
(other than contingent indemnity obligations) and the termination of the

                                       13

<PAGE>

Credit Agreement, (ii) be binding upon Grantor, its successors and assigns and
(iii) except to the extent that the rights of any transferor or assignor are
limited by the terms of the Credit Agreement, inure, together with the rights
and remedies of Administrative Agent hereunder, to the benefit of Administrative
Agent and any of the Holders of Secured Obligations. Nothing set forth herein or
in any other Loan Document is intended or shall be construed to give any other
Person any right, remedy or claim under, to or in respect of this Agreement or
any other Loan Document or any Collateral. Grantor's successors and assigns
shall include, without limitation, a receiver, trustee or debtor-in-possession
thereof or therefor.

          (b) Upon the later of (i) the payment in full in cash of the Secured
Obligations (other than contingent indemnity obligations) and (ii) the
termination of the Credit Agreement, this Agreement and the security interest
granted hereby shall terminate and all rights to the Collateral shall revert to
Grantor. Upon any such termination of security interest, Grantor shall be
entitled to the return, upon its request and at its expense, of such of the
Collateral held by Administrative Agent as shall not have been sold or otherwise
applied pursuant to the terms hereof and Administrative Agent will, at Grantor's
expense, execute and deliver to Grantor such other documents (including, but not
limited to, Uniform Commercial Code termination statements and release of
security interests for filing in the United States Patent and Trademark Office
and Copyright Office) as Grantor shall reasonably request to evidence such
termination. In connection with any sales of assets permitted under the Credit
Agreement, the Administrative Agent will release and terminate the liens and
security interests granted under this Agreement with respect to such assets.

          SECTION 21. Severability; No Strict Construction.

          (a) It is the parties' intention that this Agreement be interpreted in
such a way that it is valid and effective under applicable law. However, if one
or more of the provisions of this Agreement shall for any reason be found to be
invalid or unenforceable, the remaining provisions of this Agreement shall be
unimpaired.

          (b) The parties hereto have participated jointly in the negotiation
and drafting of this Agreement. In the event an ambiguity or question of intent
or interpretation arises, this Agreement shall be construed as if drafted
jointly by the parties hereto and no presumption or burden of proof shall arise
favoring or disfavoring any party by virtue of the authorship of any provisions
of this Agreement.

          SECTION 22. GOVERNING LAW. THE ADMINISTRATIVE AGENT ACCEPTS THIS
AGREEMENT, ON BEHALF OF ITSELF AND THE HOLDERS OF SECURED OBLIGATIONS, AT
CHICAGO, ILLINOIS BY ACKNOWLEDGING AND AGREEING TO IT THERE. THIS AGREEMENT
SHALL BE GOVERNED BY AND INTERPRETED AND ENFORCED IN ACCORDANCE WITH THE
INTERNAL LAWS (INCLUDING, WITHOUT LIMITATION, 735 ILCS 105/5-1 ET SEQ., BUT
OTHERWISE WITHOUT REGARD TO THE CONFLICTS OF LAWS PROVISIONS) OF THE STATE OF
ILLINOIS (EXCEPT TO THE EXTENT THAT THE UCC PROVIDES FOR THE APPLICATION OF LAWS
OF ANOTHER STATE). WITHOUT LIMITING THE FOREGOING, ANY DISPUTE BETWEEN THE
GRANTOR AND THE ADMINISTRATIVE AGENT, ANY LENDER, OR ANY OTHER HOLDER OF SECURED
OBLIGATIONS ARISING OUT OF, CONNECTED WITH, RELATED TO, OR INCIDENTAL TO THE

                                       14

<PAGE>

RELATIONSHIP ESTABLISHED BETWEEN THEM IN CONNECTION WITH, THIS AGREEMENT, AND
WHETHER ARISING IN CONTRACT, TORT, EQUITY, OR OTHERWISE, SHALL BE RESOLVED IN
ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF ILLINOIS.

          SECTION 23. CONSENT TO JURISDICTION; SERVICE OF PROCESS; JURY TRIAL.

          (A) CONSENT TO JURISDICTION. THE GRANTOR HEREBY IRREVOCABLY SUBMITS TO
THE NON-EXCLUSIVE JURISDICTION OF ANY UNITED STATES FEDERAL OR ILLINOIS STATE
COURT SITTING IN CHICAGO, ILLINOIS IN ANY ACTION OR PROCEEDING ARISING OUT OF OR
RELATING TO THIS AGREEMENT OR ANY LOAN DOCUMENT AND THE GRANTOR HEREBY
IRREVOCABLY AGREES THAT ALL CLAIMS IN RESPECT OF SUCH ACTION OR PROCEEDING MAY
BE HEARD AND DETERMINED IN ANY SUCH COURT AND IRREVOCABLY WAIVES ANY OBJECTION
IT MAY NOW OR HEREAFTER HAVE AS TO THE VENUE OF ANY SUCH SUIT, ACTION OR
PROCEEDING BROUGHT IN SUCH A COURT OR THAT SUCH COURT IS AN INCONVENIENT FORUM.
NOTHING HEREIN SHALL LIMIT THE RIGHT OF THE ADMINISTRATIVE AGENT OR ANY LENDER
TO BRING PROCEEDINGS AGAINST THE GRANTOR IN THE COURTS OF ANY OTHER
JURISDICTION.

          (B) OTHER JURISDICTIONS. GRANTOR AGREES THAT THE ADMINISTRATIVE AGENT,
ANY LENDER OR ANY HOLDER OF SECURED OBLIGATIONS SHALL HAVE THE RIGHT TO PROCEED
AGAINST GRANTOR OR ITS PROPERTY IN A COURT IN ANY LOCATION TO ENABLE SUCH PERSON
TO (1) OBTAIN PERSONAL JURISDICTION OVER THE GRANTOR OR (2) REALIZE ON THE
COLLATERAL OR ANY OTHER SECURITY FOR THE OBLIGATIONS OR TO ENFORCE A JUDGMENT OR
OTHER COURT ORDER ENTERED IN FAVOR OF SUCH PERSON. GRANTOR WAIVES ANY OBJECTION
THAT IT MAY HAVE TO THE LOCATION OF THE COURT IN WHICH SUCH PERSON HAS COMMENCED
A PROCEEDING DESCRIBED IN THIS SUBSECTION.

          (C) SERVICE OF PROCESS; VENUE. THE GRANTOR WAIVES PERSONAL SERVICE OF
ANY PROCESS UPON IT AND IRREVOCABLY CONSENTS TO THE SERVICE OF PROCESS OF ANY
WRITS, PROCESS OR SUMMONSES IN ANY SUIT, ACTION OR PROCEEDING BY THE MAILING
THEREOF BY THE ADMINISTRATIVE AGENT, ANY LENDER OR ANY HOLDER OF SECURED
OBLIGATIONS BY REGISTERED OR CERTIFIED MAIL, POSTAGE PREPAID, TO THE GRANTOR
ADDRESSED AS PROVIDED HEREIN. NOTHING HEREIN SHALL IN ANY WAY BE DEEMED TO LIMIT
THE ABILITY OF THE ADMINISTRATIVE AGENT, ANY LENDER OR ANY HOLDER OF SECURED
OBLIGATIONS TO SERVE ANY SUCH WRITS, PROCESS OR SUMMONSES IN ANY OTHER MANNER
PERMITTED BY APPLICABLE LAW. THE GRANTOR IRREVOCABLY WAIVES ANY OBJECTION
(INCLUDING, WITHOUT LIMITATION, ANY OBJECTION OF THE LAYING OF VENUE OR BASED ON
THE GROUNDS OF FORUM NON CONVENIENS) WHICH IT MAY NOW OR HEREAFTER HAVE TO THE
BRINGING OF ANY SUCH ACTION OR PROCEEDING WITH RESPECT TO THIS SECURITY
AGREEMENT OR ANY OTHER INSTRUMENT,

                                       15

<PAGE>

DOCUMENT OR AGREEMENT EXECUTED OR DELIVERED IN CONNECTION HEREWITH IN ANY
JURISDICTION SET FORTH ABOVE.

          (D) WAIVER OF JURY TRIAL. EACH OF THE PARTIES HERETO HEREBY WAIVES
TRIAL BY JURY IN ANY JUDICIAL PROCEEDING INVOLVING, DIRECTLY OR INDIRECTLY, ANY
MATTER (WHETHER SOUNDING IN TORT, CONTRACT OR OTHERWISE) IN ANY WAY ARISING OUT
OF, RELATED TO, OR CONNECTED WITH THIS AGREEMENT OR ANY LOAN DOCUMENT OR THE
RELATIONSHIP ESTABLISHED THEREUNDER.

          (E) WAIVER OF BOND. GRANTOR WAIVES THE POSTING OF ANY BOND OTHERWISE
REQUIRED OF ANY PARTY HERETO IN CONNECTION WITH ANY JUDICIAL PROCESS OR
PROCEEDING TO REALIZE ON THE COLLATERAL OR ANY OTHER SECURITY FOR THE SECURED
OBLIGATIONS OR TO ENFORCE ANY JUDGMENT OR OTHER COURT ORDER ENTERED IN FAVOR OF
SUCH PARTY, OR TO ENFORCE BY SPECIFIC PERFORMANCE, TEMPORARY RESTRAINING ORDER,
PRELIMINARY OR PERMANENT INJUNCTION, THIS AGREEMENT.

          (F) ADVICE OF COUNSEL. EACH OF THE PARTIES REPRESENTS TO EACH OTHER
PARTY HERETO THAT IT HAS DISCUSSED THIS AGREEMENT AND, SPECIFICALLY, THE
PROVISIONS OF THIS SECTION 23, WITH ITS COUNSEL.

               The remainder of this page is intentionally blank.

                                       16

<PAGE>

          IN WITNESS WHEREOF, Grantor has caused this Agreement to be duly
executed and delivered by its officer thereunto duly authorized 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 Administrative Agent


                                           By: /s/ Dana Jurgens
                                               ---------------------------------
                                               Name: Dana Jurgens
                                               Title: Director

                      Signature Page to Security Agreement

<PAGE>

                                    EXHIBIT A
                                       to
                               SECURITY AGREEMENT

                      Form of Restricted Account Agreement

TO: Bank One, NA, (Main Office Chicago),
    as contractual representative (the "Administrative Agent") under that
    certain Credit Agreement, dated as of September 9, 2003 (the "Credit
    Agreement"), among Bio-Rad Laboratories, Inc., a Delaware corporation
    (the "Borrower"), the Administrative Agent and those lenders from time
    to time parties thereto.

Ladies and Gentlemen:

     You have advised us that the Borrower has entered or will enter into the
Credit Agreement and that in connection therewith the Borrower has granted to
the Administrative Agent, for its benefit and the benefit of the Holders of
Secured Obligations (as defined in the Credit Agreement), a lien on and security
interest in substantially all of the assets of the Borrower, including all of
the accounts receivable and inventory of the Borrower.

     This will confirm that the Borrower and the undersigned collection bank
(the "Bank") have agreed as follows with respect to (i) the account[s]
identified on Schedule 1 attached hereto (the "Account[s]") [and (ii) the lock
box[es] identified on Schedule 2 attached hereto, to which the Borrower's
customers and other persons and entities obligated to the Borrower deliver
checks and other items of payment (said [lock box is] [lock boxes are]
hereinafter referred to [collectively] as the "Lock Box[es]")]:

     1. The Borrower and the Bank acknowledge and confirm that although the
Account[s] [and Lock Box[es]] shall remain in the name of the Borrower, all
funds now or at any time hereafter deposited to the Account[s] [and Lock
Box[es]] and all of the Borrower's rights regarding such Account[s] [and Lock
Box[es]] constitute part of the collateral in which the Borrower has granted a
security interest to the Administrative Agent, to secure the Borrower's
obligations under the Credit Agreement and the other instruments, documents and
agreements executed in connection therewith, and that during a "Notification
Period" (as defined below), the Bank shall not be permitted to follow the
Borrower's directions as to disbursements and deposits with respect thereto.
[The Bank's authorized representatives will have access to the Lock Box[es],
under the authority given by the Borrower to the appropriate Post Office, and
will make regular pick-ups from the Lock Box[es] timed to gain the maximum
benefit of early presentation and availability of funds. Upon the Bank's receipt
thereof, checks and other items of payment so received will be processed and,
where possible, started on their way through the regular channels for payment
upon receipt by the Bank. Subject to final collection, credit for such items
will be given in total on the Bank's books relating to the [appropriate]
Account. The Bank will supply the Borrower's endorsement on checks received by
it by endorsing them "Credited to the account of the within payee" and will
present them for payment through the customary collection

<PAGE>

procedures and subject to the terms of the Bank's by-laws covering the handling
of items deposited with it.]/1/

     2. The Bank will not exercise, and hereby releases, any banker's lien upon
and any right of set off against checks or other items of payment [remitted to
the Lock Box[es] and/or] deposited in the Account[s], except (i) with respect to
the Bank's normal fees and charges for operating the Account[s] and (ii) for
amounts previously credited to Borrower's Account[s] which the Bank subsequently
determines are uncollectible items. Checks returned unpaid because of
uncollected or insufficient funds shall be redeposited without advice.

     3. From and after the date on which the Administrative Agent notifies the
Bank, in writing, that it is exercising its rights under this Restricted Account
Agreement (the "Notice") until the date on which the Administrative Agent
notifies the Bank that it is withdrawing such Notice (such period being referred
to herein as a "Notification Period"), the Bank, the Borrower and the
Administrative Agent agree that, unless the Administrative Agent otherwise
instructs the Bank in writing:

          A. The Bank will not honor drafts, demands, withdrawal requests or
     remittance instructions by the Borrower.

          B. The Bank will hold solely for account of the Administrative Agent
     all funds which may be on deposit in the Account[s] and the Administrative
     Agent shall have the exclusive right to direct the Bank as to the
     disposition of all checks, other items of payment and amounts deposited in
     the Account[s] [and remitted to the Lock Box[es]].

          C. The Bank will remit all such funds directly to the Administrative
     Agent, as soon as the funds are collected, by electronic transfer of
     immediately available funds in accordance with the Administrative Agent's
     written wire-transfer instructions given from time to time to the Bank.

          D. The Bank shall be entitled to rely upon any notice or other writing
     received from the Administrative Agent, and the Borrower waives any claim
     against the Bank, and releases the Bank from any liability for, complying
     with the terms of this Restricted Account Agreement.

     4. [The Borrower will receive a receipted copy of the activity relating to
the Lock Box[es] for its records.] The Bank will not close the Account[s]
without giving the Administrative Agent at least thirty (30) days' prior written
notice at the address set forth below or such other address as the
Administrative Agent may from time to time indicate by written notice to the
Bank, and the Bank will send to the Administrative Agent at such address a copy
of each periodic statement for the Account, as and when the statement is sent to
the Borrower.

----------
/1/ The last three sentences of this Section and the last sentence of the
following Section may be substituted with a cross reference to the applicable
cash-management or lock-box services agreement, if one exists.

<PAGE>

     5. Any notice (including, without limitation, any Notice) required or
desired to be served, given or delivered hereunder shall be in writing and shall
be deemed to have been validly served, given or delivered (i) three (3) business
days after deposit in the United States mails, with proper postage prepaid, (ii)
when sent after receipt of confirmation if sent by telecopy, (iii) one (1)
business day after deposit with a reputable overnight courier with all charges
prepaid, or (iv) when delivered, if hand delivered by messenger.

     6. The Bank shall not be liable for, and the Borrower agrees to indemnify
the Bank against, any liability or claims including court costs, reasonable
attorney's fees and other expenses, which the Bank may incur in connection with
or pursuant to this Restricted Account Agreement, unless arising from the Bank's
own gross negligence or willful misconduct.

     7. This Restricted Account Agreement shall be binding upon the Bank and the
Borrower and their respective successors and assigns and shall inure to the
benefit of the Administrative Agent, each of the Holders of Secured Obligations
and their respective successors and assigns. This Restricted Account Agreement
may not be modified without the Administrative Agent's prior written consent,
but may be terminated by the Administrative Agent or the Bank upon thirty (30)
days' prior written notice to the other parties hereto.

                     [Remainder of page intentionally blank]

<PAGE>

This Restricted Account Agreement shall be deemed effective as of [___________,
20__] upon execution hereof by the Bank.

                                           [Insert full name of Bank]:


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

                                           Address:

                                           -------------------------------------

                                           -------------------------------------
                                           Attn:
                                                 -------------------------------
                                           Telecopy No.:
                                                        ------------------------
                                           Confirmation No.:
                                                            --------------------

<PAGE>

Acknowledged and agreed to as of this
[___] day of [________, 20__]:

BIO-RAD LABORATORIES, INC.


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

Address:

1000 Alfred Nobel Drive
Hercules, California 94547
Attn:
     --------------------------------------
Telecopy No.:
              -----------------------------
Confirmation No.:
                  -------------------------

Acknowledged and agreed to as of this
[___] day of [______, 20__]:

BANK ONE, NA, as Administrative Agent


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

Address:
1 Bank One Plaza
Chicago, Illinois 60670
Attn: [____________]
Telecopy No.:
              -----------
Confirmation No.:
                  -----------