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                                                                   EXHIBIT 10.42

                   [Molecular Devices Corporation letterhead]

April 11, 2002

John S. Senaldi
c/o Molecular Devices Corporation
1311 Orleans Drive
Sunnyvale, CA  94089

Dear John:

This will serve to confirm the agreement of Molecular Devices Corporation
(the "Company") that, in consideration of your election to forgo the
change-in-control severance benefits under your Employment Agreement dated
July 10, 1998 (the "Employment Agreement"), you will be entitled to benefits
under the Company's 2001 Change In Control Severance Plan (the "Plan").  In
addition, the Company hereby agrees that it will not terminate the Plan or
implement any amendment of the Plan that would result in lesser benefits to you
under the Plan than you currently have under the Employment Agreement without
(a) your written consent or (b) restoring to you your rights under the
Employment Agreement.

Very truly yours,

Molecular Devices Corporation


By: /s/ Joseph D. Keegan, Ph.D.
    ----------------------------
    Joseph D. Keegan, Ph.D.
    CEO/President


AGREED:

    /s/ John S. Senaldi
--------------------------------
    John S. Senaldi
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                          MOLECULAR DEVICES CORPORATION

                  CHANGE IN CONTROL SEVERANCE BENEFIT PLAN FOR

                                 JOHN S. SENALDI

                            VICE PRESIDENT MARKETING

SECTION 1.  INTRODUCTION.

            The Molecular Devices Corporation Change in Control Severance
Benefit Plan (the "Plan") was established effective February 15, 2001. The
purpose of the Plan is to provide for the payment of severance benefits to
certain eligible employees of Molecular Devices Corporation (the "Company")
whose employment with the Company is terminated following a Change in Control.
This Plan shall supersede any severance benefit plan, policy or practice
previously maintained by the Company. This Plan document also is the Summary
Plan Description for the Plan.

SECTION 2.  DEFINITIONS.

      For purposes of the Plan, the following terms are defined as follows:

            (a) "BASE SALARY" means the Eligible Employee's annual base salary
as in effect during the last regularly scheduled payroll period immediately
preceding the Change in Control or as increased thereafter.

            (b) "BOARD" means the Board of Directors of the Company.

            (c) "CHANGE IN CONTROL" is defined as one or more of the following
events:

                  (i) there is consummated a sale or other disposition of all or
substantially all of the assets of the Company (other than a sale to an entity
where at least fifty percent (50%) of the combined voting power of the voting
securities of such entity are owned by the stockholders of the Company in
substantially the same proportions as their ownership of the Company immediately
prior to such sale);

                  (ii) any person, entity or group (other than the Company, a
subsidiary or affiliate of the Company, or a Company employee benefit plan,
including any trustee of such plan acting as trustee) becomes the beneficial
owner, directly or indirectly, of securities of the Company representing fifty
percent (50%) or more of the combined voting power of the Company's then
outstanding securities other than by virtue of a merger, consolidation or
similar transaction; or

                  (iii) there is consummated a merger, consolidation or similar
transaction involving (directly or indirectly) the Company and, immediately
after the consummation of such transaction, the stockholders immediately prior
to the consummation of

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such transaction do not own, directly or indirectly, outstanding voting
securities representing more than fifty percent (50%) of the combined
outstanding voting power of the surviving entity in such transaction or more
than fifty percent (50%) of the combined outstanding voting power of the parent
of the surviving entity in such transaction.

            (d) "COMPANY" means Molecular Devices Corporation or, following a
Change in Control, the surviving entity resulting from such transaction.

            (e) "CONSTRUCTIVE TERMINATION" means a voluntary termination of
employment by an Eligible Employee after one of the following is undertaken
without the Eligible Employee's express written consent:

                  (i) the assignment to the Eligible Employee of duties or
responsibilities that results in a material diminution in the Eligible
Employee's authority, duties or responsibilities as in effect immediately prior
to the Change in Control; provided, however, that a mere change in the Eligible
Employee's title or reporting relationships shall not provide the basis for a
Constructive Termination;

                  (ii) a reduction in the Eligible Employee's base salary, as in
effect immediately prior to the Change in Control (or as increased thereafter),
unless such reduction is made pursuant to an across-the-board reduction of the
base salaries of all similarly situated employees of the Company of no more than
ten percent (10%);

                  (iii) a change in the Eligible Employee's business location of
more than 35 miles from the business location immediately prior to the Change in
Control;

                  (iv) a material breach by the Company of any provisions of the
Plan or any enforceable written agreement between the Company and the Eligible
Employee; or

                  (v) any failure by the Company to obtain assumption of the
Plan by any successor or assign of the Company.

            (f) "CONTINUATION PERIOD" means the period for which an Eligible
Employee is entitled to receive the benefits described in Section 4(c). The
Continuation Period is eighteen (18) months.

            (g) "COVERED TERMINATION" means an Involuntary Termination Without
Cause or a Constructive Termination, either of which occurs within thirteen (13)
months following the effective date of a Change in Control.

            (h) "INVOLUNTARY TERMINATION WITHOUT CAUSE" means an involuntary
termination of employment by the Company other than for one of the following
reasons:

                  (i) refusal or failure to follow the lawful and reasonable
directions of the Board of Directors or individual to whom the Eligible Employee
reports, which refusal or failure is not cured within 30 days following delivery
of written notice of such conduct to the Eligible Employee;

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                  (ii) a material failure by the Eligible Employee to perform
his or her duties in a manner reasonably satisfactory to the Board of Directors
that is not cured within 30 days following delivery of written notice of such
failure to the Eligible Employee; or

                  (iii) conviction of a felony involving moral turpitude that is
likely to inflict or has inflicted material injury on the business of the
Company.

SECTION 3.  ELIGIBILITY FOR BENEFITS.

            (a) GENERAL RULES. Subject to the requirements set forth in this
Section, the Company will provide the severance benefits described in Section 4
of the Plan to Eligible Employees. For purposes of this Plan, "Eligible
Employees" are designated executive employees of the Company who have not
entered into individual severance benefit or change in control agreements with
the Company and whose employment with the Company terminates due to a Covered
Termination.

                  (i) In order to be eligible to receive benefits under the
Plan, an Eligible Employee must remain on the job until his or her date of
termination, as scheduled by the Company.

                  (ii) In order to be eligible to receive benefits under the
Plan, an Eligible Employee also must execute a general waiver and release in
substantially the form attached hereto as Exhibit A, Exhibit B or Exhibit C, as
appropriate, and such release must become effective in accordance with its
terms. The Company, in its sole discretion, may modify the form of the required
release to comply with applicable state law. Subject to the foregoing, the
Company, in its sole discretion, shall determine the form of the required
release.

                (b) EXCEPTIONS TO BENEFIT ENTITLEMENT. An employee who otherwise
is an Eligible Employee will not receive benefits under the Plan in any of the
following circumstances, as determined by the Company in its sole discretion:

                  (i) The employee has executed an individually negotiated
employment contract or agreement with the Company relating to severance benefits
or change in control benefits that is in effect on his or her termination date.

                  (ii) The employee's employment with the Company is
involuntarily terminated by the Company other than as an Involuntary Termination
without Cause.

                  (iii) The employee voluntarily terminates employment with the
Company and such termination does not constitute a Constructive Termination.
Voluntary terminations include, but are not limited to, resignation, retirement
or failure to return from a leave of absence on the scheduled date.

                  (iv) The employee voluntarily terminates employment with the
Company in order to accept employment with another entity that is wholly or
partly owned (directly or indirectly) by the Company or an affiliate of the
Company.

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SECTION 4.  AMOUNT OF BENEFIT.

            (a) BASE SALARY. Each Eligible Employee shall receive twelve (12)
months of Base Salary. Such amount shall be paid in a lump sum and shall be
subject to all required tax withholding.

            (b) BONUS PAYMENT. Each Eligible Employee shall receive a bonus
payment equal to what would have been earned at one hundred percent (100%) of
target for the year of termination.

            (c) CONTINUED INSURANCE BENEFITS. Provided that the Eligible
Employee elects continued coverage under the Consolidated Omnibus Budget
Reconciliation Act of 1985 ("COBRA"), the Company shall pay the portion of
premiums of each Eligible Employee's group medical, dental and vision coverage,
including coverage for the Eligible Employee's eligible dependents, that the
Company paid prior to the Covered Termination, for eighteen (18) months;
provided, however, that no such premium payments shall be made following the
effective date of the Eligible Employee's coverage by a medical, dental or
vision insurance plan of a subsequent employer. Each Eligible Employee shall be
required to notify the Company immediately if the Eligible Employee becomes
covered by a medical, dental or vision insurance plan of a subsequent employer.
No provision of this Plan will affect the continuation coverage rules under
COBRA, except that the Company's payment of any applicable insurance premiums
during the Continuation Period will be credited as payment by the Eligible
Employee for purposes of the Eligible Employee's payment required under COBRA.
Therefore, the period during which an Eligible Employee must elect whether or
not to continue the Company's group medical, dental or vision coverage under
COBRA, the length of time during which COBRA continuation coverage will be made
available to the Eligible Employee, and all other rights and obligations of the
Eligible Employee under COBRA will be applied in the same manner that such rules
would apply in the absence of this Plan. At the conclusion of the Continuation
Period, the Eligible Employee will be responsible for the entire payment of
premiums required under COBRA for the duration of the COBRA continuation period.
For purposes of this Section 4(c), applicable premiums that will be paid by the
Company during the Continuation Period shall not include any amounts payable by
the Eligible Employee under a Section 125 health care reimbursement plan, which
amounts, if any, are the sole responsibility of the Eligible Employee.

            (d) ACCELERATION OF VESTING. Effective as of the date of the Covered
Termination, each Eligible Employee shall be credited with full acceleration of
vesting for all options outstanding that the Eligible Employee holds on such
date that have not yet vested. Notwithstanding the foregoing, if the acquiring
entity in the transaction which constitutes a Change in Control under the Plan
intends to utilize the "pooling of interests" accounting method in connection
with such transaction, and such transaction would be eligible for the "pooling
of interests" accounting method but for the additional vesting credit provided
for in this Section 4(d), then Eligible Employees shall not be entitled to
receive such additional vesting credit.

            (e) OUTPLACEMENT SERVICES. On behalf of the Eligible Employee, the
Company shall pay for an executive assistance program for a period not to exceed
three (3) months and at a cost not to exceed $7,500, provided that the Eligible
Employee enrolls in the program within six (6) months following the Covered
Termination.

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SECTION 5.  LIMITATIONS ON BENEFITS.

            (a) RELEASE. To receive benefits under this Plan, an Eligible
Employee must execute a release of claims in favor of the Company, in the form
attached to this Plan as Exhibit A, Exhibit B or Exhibit C, as appropriate, and
such release must become effective in accordance with its terms.

            (b) CERTAIN REDUCTIONS AND OFFSETS. Notwithstanding any other
provision of the Plan to the contrary, any benefits payable to an Eligible
Employee under this Plan shall be reduced by any severance benefits payable by
the Company to such individual under any other policy, plan, program or
arrangement, including, without limitation, a contract between the Eligible
Employee and any entity, covering such individual. Furthermore, to the extent
that any federal, state or local laws, including, without limitation, so-called
"plant closing" laws, require the Company to give advance notice or make a
payment of any kind to an Eligible Employee because of that Eligible Employee's
involuntary termination due to a layoff, reduction in force, plant or facility
closing, sale of business, change of control, or any other similar event or
reason, the benefits payable under this Plan shall either be reduced or
eliminated. The benefits provided under this Plan are intended to satisfy any
and all statutory obligations that may arise out of an Eligible Employee's
involuntary termination of employment for the foregoing reasons, and the Plan
Administrator shall so construe and implement the terms of the Plan.

            (c) MITIGATION. Except as otherwise specifically provided herein,
Eligible Employees shall not be required to mitigate damages or the amount of
any payment provided under this Plan by seeking other employment or otherwise,
nor shall the amount of any payment provided for under this Plan be reduced by
any compensation earned by any Eligible Employee as a result of employment by
another employer or any retirement benefits received by such Eligible Employee
after the date of the Covered Termination.

            (d) TERMINATION OF BENEFITS. Benefits under this Plan shall
terminate immediately if the Eligible Employee, at any time, violates any
proprietary information or confidentiality obligation to the Company.

            (e) NON-DUPLICATION OF BENEFITS. No Eligible Employee is eligible to
receive benefits under this Plan more than one time.

            (f) INDEBTEDNESS OF ELIGIBLE EMPLOYEES. If a terminating employee is
indebted to the Company or an affiliate of the Company at his or her termination
date, the Company reserves the right to offset any severance payments under the
Plan by the amount of such indebtedness.

            (g) PARACHUTE PAYMENTS. If any payment or benefit the Eligible
Employee would receive in connection with a Change in Control from the Company
or otherwise ("Payment") would (i) constitute a "parachute payment" within the
meaning of Section 280G of the Internal Revenue Code of 1986, as amended (the
"Code"), and (ii) but for this sentence, be subject to the excise tax imposed by
Section 4999 of the Code (the "Excise Tax"), then such Payment shall be reduced
to the Reduced Amount. The "Reduced Amount" shall be either (x) the largest
portion of the Payment that would result in no portion of the Payment being
subject to

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the Excise Tax or (y) the largest portion, up to and including the total, of the
Payment, whichever amount, after taking into account all applicable federal,
state and local employment taxes, income taxes, and the Excise Tax (all computed
at the highest applicable marginal rate), results in the Eligible Employee's
receipt, on an after-tax basis, of the greater amount of the Payment
notwithstanding that all or some portion of the Payment may be subject to the
Excise Tax. If a reduction in payments or benefits constituting "parachute
payments" is necessary so that the Payment equals the Reduced Amount, reduction
shall occur in the following order unless the Eligible Employee elects in
writing a different order (provided, however, that such election shall be
subject to Company approval if made on or after the date on which the event that
triggers the Payment occurs): reduction of cash payments; cancellation of
accelerated vesting of stock awards; reduction of employee benefits. In the
event that acceleration of vesting of stock award compensation is to be reduced,
such acceleration of vesting shall be cancelled in the reverse order of the date
of grant of the Eligible Employee's stock awards unless the Eligible Employee
elects in writing a different order for cancellation.

      The accounting firm engaged by the Company for general audit purposes as
of the day prior to the effective date of the Change in Control shall perform
the foregoing calculations. If the accounting firm so engaged by the Company is
serving as accountant or auditor for the individual, entity or group effecting
the Change in Control, the Company shall appoint a nationally recognized
accounting firm to make the determinations required hereunder. The Company shall
bear all expenses with respect to the determinations by such accounting firm
required to be made hereunder.

      The accounting firm engaged to make the determinations hereunder shall
provide its calculations, together with detailed supporting documentation, to
the Company and the Eligible Employee within fifteen (15) calendar days after
the date on which the Eligible Employee's right to a Payment is triggered (if
requested at that time by the Company or the Eligible Employee) or such other
time as requested by the Company or the Eligible Employee. If the accounting
firm determines that no Excise Tax is payable with respect to a Payment, either
before or after the application of the Reduced Amount, it shall furnish the
Company and the Eligible Employee with an opinion reasonably acceptable to
Executive that no Excise Tax will be imposed with respect to such Payment. Any
good faith determinations of the accounting firm made hereunder shall be final,
binding and conclusive upon the Company and the Eligible Employee.

SECTION 6.  RIGHT TO INTERPRET PLAN; AMENDMENT AND TERMINATION.

            (a) EXCLUSIVE DISCRETION. The Plan Administrator shall have the
exclusive discretion and authority to establish rules, forms, and procedures for
the administration of the Plan and to construe and interpret the Plan and to
decide any and all questions of fact, interpretation, definition, computation or
administration arising in connection with the operation of the Plan, including,
but not limited to, the eligibility to participate in the Plan and amount of
benefits paid under the Plan. The rules, interpretations, computations and other
actions of the Plan Administrator shall be binding and conclusive on all
persons.

            (b) AMENDMENT OR TERMINATION. The Company reserves the right to
amend or terminate this Plan or the benefits provided hereunder at any time;
provided, however, that no such amendment or termination shall occur following a
Change in Control if such amendment or

<PAGE>
termination would affect the rights of any persons who were employed by the
Company prior to the Change in Control. Any action amending or terminating the
Plan shall be in writing and executed by the chairman of the Compensation
Committee of the Board of Directors of the Company.

SECTION 7.  TERMINATION OF CERTAIN EMPLOYEE BENEFITS.

            All non-health benefits (such as life insurance, disability and
401(k) plan coverage) terminate as of the employee's termination date (except to
the extent that a conversion privilege may be available thereunder).

SECTION 8.  NO IMPLIED EMPLOYMENT CONTRACT.

            The Plan shall not be deemed (i) to give any employee or other
person any right to be retained in the employ of the Company or (ii) to
interfere with the right of the Company to discharge any employee or other
person at any time and for any reason, which right is hereby reserved.

SECTION 9.  LEGAL CONSTRUCTION.

            This Plan is intended to be governed by and shall be construed in
accordance with the Employee Retirement Income Security Act of 1974 ("ERISA")
and, to the extent not preempted by ERISA, the laws of the State of California.

SECTION 10. CLAIMS, INQUIRIES AND APPEALS.

            (a)   APPLICATIONS FOR BENEFITS AND INQUIRIES.  Any application
for benefits, inquiries about the Plan or inquiries about present or future
rights under the Plan must be submitted to the Plan Administrator in
writing.  The Plan Administrator is:

                          Molecular Devices Corporation
                      Attn: Vice President, Human Resources
                               1311 Orleans Drive
                               Sunnyvale, CA 94089

            (b) DENIAL OF CLAIMS. In the event that any application for benefits
is denied in whole or in part, the Plan Administrator must notify the applicant,
in writing, of the denial of the application, and of the applicant's right to
review the denial. The written notice of denial will be set forth in a manner
designed to be understood by the employee and will include specific reasons for
the denial, specific references to the Plan provision upon which the denial is
based, a description of any information or material that the Plan Administrator
needs to complete the review and an explanation of the Plan's review procedure.

            This written notice will be given to the employee within ninety (90)
days after the Plan Administrator receives the application, unless special
circumstances require an extension of time, in which case, the Plan
Administrator has up to an additional ninety (90) days for processing the
application. If an extension of time for processing is required, written notice
of

<PAGE>
the extension will be furnished to the applicant before the end of the initial
ninety (90) day period.

            This notice of extension will describe the special circumstances
necessitating the additional time and the date by which the Plan Administrator
is to render its decision on the application. If written notice of denial of the
application for benefits is not furnished within the specified time, the
application shall be deemed to be denied. The applicant will then be permitted
to appeal the denial in accordance with the Review Procedure described below.

            (c) REQUEST FOR A REVIEW. Any person (or that person's authorized
representative) for whom an application for benefits is denied (or deemed
denied), in whole or in part, may appeal the denial by submitting a request for
a review to the Plan Administrator within sixty (60) days after the application
is denied (or deemed denied). The Plan Administrator will give the applicant (or
his or her representative) an opportunity to review pertinent documents in
preparing a request for a review. A request for a review shall be in writing and
shall be addressed to:

                          Molecular Devices Corporation
                      Attn: Vice President, Human Resources
                               1311 Orleans Drive
                               Sunnyvale, CA 94089

A request for review must set forth all of the grounds on which it is based, all
facts in support of the request and any other matters that the applicant feels
are pertinent. The Plan Administrator may require the applicant to submit
additional facts, documents or other material as it may find necessary or
appropriate in making its review.

            (d) DECISION ON REVIEW. The Plan Administrator will act on each
request for review within sixty (60) days after receipt of the request, unless
special circumstances require an extension of time (not to exceed an additional
sixty (60) days), for processing the request for a review. If an extension for
review is required, written notice of the extension will be furnished to the
applicant within the initial sixty (60) day period. The Plan Administrator will
give prompt, written notice of its decision to the applicant. In the event that
the Plan Administrator confirms the denial of the application for benefits in
whole or in part, the notice will outline, in a manner calculated to be
understood by the applicant, the specific Plan provisions upon which the
decision is based. If written notice of the Plan Administrator's decision is not
given to the applicant within the time prescribed in this Subsection (d), the
application will be deemed denied on review.

            (e) RULES AND PROCEDURES. The Plan Administrator will establish
rules and procedures, consistent with the Plan and with ERISA, as necessary and
appropriate in carrying out its responsibilities in reviewing benefit claims.
The Plan Administrator may require an applicant who wishes to submit additional
information in connection with an appeal from the denial (or deemed denial) of
benefits to do so at the applicant's own expense.

<PAGE>
            (f) EXHAUSTION OF REMEDIES. No legal action for benefits under the
Plan may be brought until the claimant (i) has submitted a written application
for benefits in accordance with the procedures described by Section 10(a) above,
(ii) has been notified by the Plan Administrator that the application is denied
(or the application is deemed denied due to the Plan Administrator's failure to
act on it within the established time period), (iii) has filed a written request
for a review of the application in accordance with the appeal procedure
described in Section 10(c) above and (iv) has been notified in writing that the
Plan Administrator has denied the appeal (or the appeal is deemed to be denied
due to the Plan Administrator's failure to take any action on the claim within
the time prescribed by Section 10(d) above).

SECTION 11. BASIS OF PAYMENTS TO AND FROM PLAN.

            All benefits under the Plan shall be paid by the Company. The Plan
shall be unfunded, and benefits hereunder shall be paid only from the general
assets of the Company.

SECTION 12. OTHER PLAN INFORMATION.

            (a) EMPLOYER AND PLAN IDENTIFICATION NUMBERS. The Employer
Identification Number assigned to the Company (which is the "Plan Sponsor" as
that term is used in ERISA) by the Internal Revenue Service is 94-2914362. The
Plan Number assigned to the Plan by the Plan Sponsor pursuant to the
instructions of the Internal Revenue Service is [510].

            (b)   ENDING DATE FOR PLAN'S FISCAL YEAR.  The date of the end of
the fiscal year for the purpose of maintaining the Plan's records is December
31.

            (c) AGENT FOR THE SERVICE OF LEGAL PROCESS. The agent for the
service of legal process with respect to the Plan is Molecular Devices
Corporation, Attn: Vice President, Human Resources, 1311 Orleans Drive,
Sunnyvale, CA 94089.

            (d)   PLAN SPONSOR AND ADMINISTRATOR.  The "Plan Sponsor" and the
"Plan Administrator" of the Plan is Molecular Devices Corporation,  Attn:
Vice President, Human Resources, 1311 Orleans Drive, Sunnyvale, CA 94089.
The Plan Sponsor's and Plan Administrator's telephone number is (408)
747-1700.  The Plan Administrator is the named fiduciary charged with the
responsibility for administering the Plan.

SECTION 13. STATEMENT OF ERISA RIGHTS.

      Participants in this Plan (which is a welfare benefit plan sponsored by
Molecular Devices Corporation) are entitled to certain rights and protections
under ERISA. An Eligible Employee is considered a participant in the Plan and,
under ERISA, is entitled to:

            (a) Examine, without charge, at the Plan Administrator's office and
at other specified locations, such as work sites, all Plan documents and copies
of all documents filed by the Plan with the U.S. Department of Labor, such as
detailed annual reports;

<PAGE>
            (b) Obtain copies of all Plan documents and Plan information upon
written request to the Plan Administrator. The Administrator may make a
reasonable charge for the copies; and

            (c) Receive a summary of the Plan's annual financial report, in the
case of a plan that is required to file an annual financial report with the
Department of Labor. (Generally, all pension plans and welfare plans with one
hundred (100) or more participants must file these annual reports.)

      In addition to creating rights for Plan participants, ERISA imposes duties
upon the people responsible for the operation of the employee benefit plan. The
people who operate the Plan, called "fiduciaries" of the Plan, have a duty to do
so prudently and in the interest of the Eligible Employees and other Plan
participants and beneficiaries.

      No one, including the employer of the participants or any other person,
may fire a participant or otherwise discriminate against participants in any way
to prevent a participant from obtaining a Plan benefit or exercising his or her
rights under ERISA. If a participant's claim for a Plan benefit is denied in
whole or in part, he or she must receive a written explanation of the reason for
the denial. A participant has the right to have the Plan Administrator review
and reconsider his or her claim.

      Under ERISA, there are steps a participant can take to enforce the above
rights. For instance, if a participant requests materials from the Plan
Administrator and does not receive them within thirty (30) days, he or she may
file suit in a federal court. In such a case, the court may require the Plan
Administrator to provide the materials and pay the participant up to $110 a day
until he or she receives the materials, unless the materials were not sent
because of reasons beyond the control of the Plan Administrator. If a
participant has a claim for benefits that is denied or ignored, in whole or in
part, he or she may file suit in a state or federal court. If it should happen
that the Plan fiduciaries misuse the Plan's money, or if a participant is
discriminated against for asserting his or her rights, the participant may seek
assistance from the U.S. Department of Labor, or he or she may file suit in a
federal court. The court will decide who should pay court costs and legal fees.
If the participant is successful, the court may order the person the participant
has sued to pay these costs and fees. If the participant loses, the court may
order the participant to pay these costs and fees, for example, if it finds his
or her claim is frivolous.

      If a participant has any questions about the Plan, the participant should
contact the Plan Administrator. If a participant has any questions about this
statement or about his or her rights under ERISA, the participant should contact
the nearest office of the Pension and Welfare Benefits Administration, U.S.
Department of Labor, listed in the telephone directory or the Division of
Technical Assistance and Inquiries, Pension and Welfare Benefits Administration,
U.S. Department of Labor, 200 Constitution Avenue N.W., Washington, D.C. 20210.

<PAGE>

SECTION 14. EXECUTION.

            To record the adoption of the Plan as set forth herein, effective as
of February 15, 2001, Molecular Devices Corporation has caused its duly
authorized officer to execute the same this 15th day of August, 2001.

                                          MOLECULAR DEVICES CORPORATION

                                          By:    /s/ JOHN S. SENALDI
                                                 -------------------------------
                                          Title: VICE PRESIDENT MARKETING