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                                                                   Exhibit 10.24

                                 CELLOMICS, INC.

                          EMPLOYEE STOCK PURCHASE PLAN

                                 I. DEFINITIONS

         ACCOUNT means the Employee Stock Purchase Plan Account established for
a Participant under Section IX hereunder.

         BOARD OF DIRECTORS shall mean the Board of Directors of the Company.

         CODE shall mean the Internal Revenue Code of 1986, as amended.

         COMMITTEE shall mean the Compensation Committee of the Board of
Directors.

         COMMON STOCK shall mean shares of the Company's Common Stock, par value
$.01 per share, and any security into which such stock shall be converted or
shall become by reason of changes in its nature such as by way of
recapitalization, reclassification, changes in par value, merger, consolidation
or similar transaction.

         COMPANY shall mean Cellomics, Inc., a Delaware corporation. When used
in the Plan with reference to employment, Company shall include Subsidiaries.

         COMPENSATION shall mean the total cash compensation paid to an Eligible
Employee by the Company, as reportable on IRS Form W-2. Notwithstanding the
foregoing, Compensation shall exclude severance pay, stay-on bonuses, long term
bonuses, retirement income, change-in-control payments, contingent payments,
income derived from stock options, stock appreciation rights and other
equity-based compensation and other forms of special remuneration.

         EFFECTIVE DATE shall mean the date of effectiveness of the Company's
Registration Statement relating to the initial public offering of the Company's
Common Stock.

         ELIGIBLE EMPLOYEES shall mean only those persons who, as of the first
day of a Purchase Period, are Employees of the Company and who are not, as of
the day preceding the first day of the Purchase Period, deemed for purposes of
Section 423(b)(3) of the Code to own stock possessing 5% or more of the total
combined voting power or value of all classes of stock of the Company.

         EMPLOYEES shall mean all persons who are employed by the Company as
common-law employees, excluding persons (i) whose customary employment is 20
hours or less per week, or (ii) whose customary employment is for not more than
five months in a calendar year.

         EXERCISE DATE shall mean the last day of a Purchase Period.



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         FAIR MARKET VALUE shall mean: (i) as of the Effective Date the initial
public offering price of the Company's Common Stock as approved by the Board of
Directors; or (ii) as of any date subsequent to the Effective Date, the last
reported sales price of the Common Stock on such date as reported by the Nasdaq
National Market or the principal national securities exchange on which such
stock is listed and traded, or in each such case where there is no trading on
such date, on the first previous date on which there is such trading.

         PARTICIPANT shall mean an Eligible Employee who elects to participate
in the Plan under Section VII hereunder.

         PLAN shall mean the Cellomics, Inc. Employee Stock Purchase Plan, as
set forth herein and as amended from time to time.

         PURCHASE PERIOD shall mean: (a) for the initial purchase period, the
period commencing on the Effective Date and ending on December 31, 2000; and (b)
thereafter, purchase periods shall be semi-annual or as otherwise elected by the
Committee not less than 60 days in advance of the commencement of such period. A
Purchase Period shall begin on the first business day of, and end on the last
business day of, each such calendar period. The last Purchase Period under the
Plan shall terminate on or before the date of termination of the Plan provided
in Section XXIV.

         SUBSIDIARY shall mean any corporation which is a subsidiary of the
Company within the meaning of Section 424(f) of the Code.

         TERMINATION OF SERVICE shall mean the earliest of the following events
with respect to a Participant: his or her retirement, death, quit, discharge or
permanent separation from service with the Company.

         The masculine gender includes the feminine, the singular number
includes the plural and the plural number includes the singular unless the
context otherwise requires.

                                  II. PURPOSE

         It is the purpose of this Plan to provide a means whereby Eligible
Employees may purchase Common Stock through payroll deductions. It is intended
to provide a further incentive for Employees to promote the best interests of
the Company and to encourage stock ownership by Employees in order to
participate in the Company's economic progress.

         It is the intention of the Company to have the Plan qualify as an
"employee stock purchase plan" within the meaning of Section 423 of the Code and
the provisions of the Plan shall be construed in a manner consistent with the
Code.

                              III. ADMINISTRATION

         The Plan shall be administered by the Committee. The Committee shall
have authority to make rules and regulations for the administration of the Plan,
and its interpretations and




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decisions with regard thereto shall be final and conclusive. The Committee shall
have all necessary authority to communicate, from time to time, with Eligible
Employees and Participants for purposes of administering the Plan, and shall
notify Eligible Employees promptly of its election of the term of each
forthcoming Purchase Period, if other than semi-annual, and of its election to
utilize the Trust Administration Option referred to in Section IX.

                                   IV. SHARES

         There shall be 300,000 shares of Common Stock reserved for issuance to
and purchase by Participants under the Plan, subject to adjustment in accordance
with Section XXI hereof. The shares of Common Stock subject to the Plan shall be
either shares of authorized but unissued Common Stock or shares of Common Stock
reacquired by the Company. Shares of Common Stock covered by the unexercised
portion of any terminated purchase right may again be subject to purchase rights
granted under the Plan.

                               V. PURCHASE PRICE

         The purchase price per share of the shares of Common Stock sold to
Participants under this Plan for any Purchase Period shall be the lesser of (a)
85% of the Fair Market Value of a share of Common Stock on the first day of such
Purchase Period, or (b) 85% of the Fair Market Value of a share of Common Stock
on the Exercise Date of such Purchase Period.

                 VI. GRANT OF PURCHASE RIGHT TO PURCHASE SHARES

         Each Eligible Employee shall be granted a purchase right effective on
the first day of each Purchase Period to purchase a number of full shares of
Common Stock (subject to adjustment as provided in Section XXI). No Eligible
Employee shall be permitted to purchase shares under this Plan (or under any
other "employee stock purchase plan" within the meaning of Section 423(b) of the
Code, of the Company ) with an aggregate Fair Market Value (as determined as of
the first day of the Purchase Period) in excess of $25,000 for any one calendar
year within the meaning of Section 423(b)(8) of the Code. For a given Purchase
Period, payroll deductions shall commence on the first day of the Purchase
Period and shall end on the related Exercise Date, unless sooner altered or
terminated as provided in the Plan.

         Anything herein to the contrary notwithstanding, if, as of the first
day of a Purchase Period, any Eligible Employee entitled to purchase shares
hereunder would be deemed for the purposes of Section 423(b)(3) of the Code to
own stock (including any number of shares which such person would be entitled to
purchase hereunder) possessing 5% or more of the total combined voting power or
value of all classes of stock of the Company, the maximum number of shares which
such person shall be entitled to purchase pursuant to the Plan shall be reduced
to that number which when added to the number of shares of stock of the Company
which such person is so deemed to own (excluding any number of shares which such
person would be entitled to purchase hereunder), is one less than such 5%.




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                          VII. ELECTION TO PARTICIPATE

         An Eligible Employee may elect to become a Participant in this Plan by
completing a "Stock Purchase Agreement" form prior to the first day of the
Purchase Period. In the Stock Purchase Agreement, the Eligible Employee shall
authorize regular, "after tax" payroll deductions from his Compensation subject
to the limitations in Section VIII below. Purchase rights granted to Eligible
Employees who fail to authorize payroll deductions will automatically lapse. If
a Participant's payroll deductions allow him to purchase fewer than the maximum
number of shares of Common Stock to which his purchase rights entitle him, the
purchase rights with respect to the shares which he does not purchase will lapse
as of the last day of the Purchase Period.

         The execution and delivery of the Stock Purchase Agreement as between
the Participant and the Company shall be conditioned upon the compliance by the
Company at such time with Federal (and any applicable state) securities laws.

                            VIII. PAYROLL DEDUCTIONS

         An Eligible Employee may authorize payroll deductions from his
Compensation for each payroll period of a specified percentage of such
Compensation, not less than 1.0% and not more than 25%, in multiples of 1.0%.

         The amount of payroll deduction shall be established at the beginning
of a Purchase Period and may not be altered, except for complete discontinuance
under Section XI, XIII or XIV hereunder.

                      IX. EMPLOYEE STOCK PURCHASE ACCOUNT
                         AND TRUST ADMINISTRATION OPTION

         An Employee Stock Purchase Account will be established for each
Participant in the Plan. Payroll deductions made under Section VIII will be
credited to the individual Accounts. No interest or other earnings will be
credited to a Participant's Account and the assets of all such Accounts shall
remain general assets of the Company until such assets are used to purchase
Common Stock in accordance with Section X hereunder.

                             X. PURCHASE OF SHARES

         If, as of any Exercise Date, there is credited to the Account of a
Participant an amount at least equal to the purchase price of one share of
Common Stock for the current Purchase Period, as determined in Section V, the
Participant shall buy and the Company shall sell at such price the largest
number of whole shares of Common Stock which can be purchased with the amount in
his Account.


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         Any balance remaining in a Participant's Account at the end of a
Purchase Period will be carried forward into the Participant's Account for the
following Purchase Period. In no event will the balance carried forward be equal
to or exceed the purchase price of one share of Common Stock as determined in
Section V above. Notwithstanding the foregoing provisions of this paragraph, if
as of any Exercise Date the provisions of Section XV are applicable to the
Purchase Period ending on such Exercise Date, and the Committee reduces the
number of shares which would otherwise be purchased by Participants on such
Exercise Date, the entire balance remaining credited to the Account of each
Participant after the purchase of the applicable number of shares of Common
Stock on such Exercise Date shall be refunded to each such Participant. Except
with respect to a Purchase Period for which the Trust Administration Option has
been elected, no refund of an Account balance made pursuant to the Plan shall
include any amount in respect of interest or other imputed earnings.

         Anything herein to the contrary notwithstanding, no Participant may, in
any calendar year, purchase a number of shares of Common Stock under this Plan
which, together with all other shares of stock of the Company and its
Subsidiaries which he may be entitled to purchase in such year under all other
employee stock purchase plans of the Company and its Subsidiaries which meet the
requirements of Section 423(b) of the Code, have an aggregate Fair Market Value
(measured as of the first day of each applicable Purchase Period) in excess of
$25,000. The limitation described in the preceding sentence shall be applied in
a manner consistent with Section 423(b)(8) of the Code.

                                 XI. WITHDRAWAL

         A Participant may withdraw from the Plan at any time prior to the
Exercise Date of a Purchase Period by filing a notice of withdrawal. Upon a
Participant's withdrawal, the payroll deductions shall cease for the next
payroll period and the entire amount credited to his Account shall be refunded
to him. Any Participant who withdraws from the Plan may again become a
Participant hereunder at the start of the next Purchase Period in accordance
with Section VII.

                      XII. ISSUANCE OF STOCK CERTIFICATES

         The shares of Common Stock purchased by a Participant shall, for all
purposes, be deemed to have been issued and sold at the close of business on the
Exercise Date. Prior to that date, none of the rights or privileges of a
stockholder of the Company shall exist with respect to such shares. Stock
certificates shall be registered either in the Participant's name or jointly in
the names of the Participant and his spouse, as the Participant shall designate
in his Stock Purchase Agreement. Such designation may be changed at any time by
filing notice thereof. Certificates representing shares of purchased Common
Stock shall be delivered promptly to the Participant following issuance.
Notwithstanding any provision hereof to the contrary, no shares of Common Stock
shall be issued, sold, registered or delivered pursuant to this Section XII or
otherwise under the Plan unless such issuance, sale, registration or delivery
shall comply with all relevant provisions of law, including, without limitation,
the Securities Act of 1933, as amended, the Exchange Act, the rules and
regulations promulgated thereunder, and the requirements of any




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stock exchange upon which the shares of Common Stock may then be listed, and
shall be further subject to the approval of counsel for the Company with respect
to such compliance.

                          XIII. TERMINATION OF SERVICE

         (a) Upon a Participant's Termination of Service for any reason other
than death or voluntary termination of employment on or after attaining age 55
("Retirement"), no payroll deduction may be made from any Compensation due him
as of the date of his Termination of Service and the entire balance credited to
his Account shall be automatically refunded to him.

         (b) Upon a Participant's Retirement, no payroll deduction shall be made
from any Compensation due him as of the date of his retirement. Such a
Participant may, prior to Retirement, elect:

                  (1) to have the entire amount credited to his Account as of
         the date of his Retirement refunded to him, or

                  (2) to have the entire amount credited to his Account held
         therein and utilized to purchase shares on the Exercise Date as
         provided in Section X and in accordance with all applicable
         requirements of the Code relating to the Plan.

         (c) Upon the death of a Participant, no payroll deduction shall be made
from any Compensation due him at time of death, and the entire balance in the
deceased Participant's Account shall be paid to the Participant's designated
beneficiary, or otherwise to his estate.

                    XIV. TEMPORARY LAYOFF, AUTHORIZED LEAVE
                             OF ABSENCE, DISABILITY

         Payroll deductions shall cease during a period of absence without pay
from work due to a Participant's temporary layoff, authorized leave of absence,
disability or for any other reason. If such Participant shall return to active
service prior to the Exercise Date for the current Purchase Period, payroll
deductions shall be resumed in accordance with his prior authorization.

         If the Participant shall not return to active service prior to the
Exercise Date for the current Purchase Period, the balance of his Stock Purchase
Account will be used to purchase shares on the Exercise Date as provided in
Section X and in accordance with all applicable requirements of the Code
relating to the Plan, unless the Participant elects to withdraw from the Plan in
accordance with Section XI.

                 XV. PROCEDURE IF INSUFFICIENT SHARES AVAILABLE

         In the event that on any Exercise Date the aggregate funds available
for the purchase of shares of Common Stock pursuant to Section X hereof would
result in purchases of shares in excess of the number of shares of Common Stock
then available for purchase under the Plan, the



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Committee shall proportionately reduce the number of shares which would
otherwise be purchased by each Participant on the Exercise Date in order to
eliminate such excess, and the provisions of the second paragraph of Section X
shall apply.

                          XVI. RIGHTS NOT TRANSFERABLE

         The right to purchase shares of Common Stock under this Plan is
exercisable only by the Participant during his lifetime and is not transferable
by him. If a Participant attempts to transfer his right to purchase shares under
the Plan, he shall be deemed to have requested withdrawal from the Plan and the
provisions of Section XI hereof shall apply with respect to such Participant.

                XVII. NO OBLIGATION TO EXERCISE PURCHASE RIGHTS

         Granting of a purchase right under this Plan shall impose no obligation
on an Eligible Employee to exercise such purchase right.

                  XVIII. NO GUARANTEE OF CONTINUED EMPLOYMENT

         Granting of a purchase right under this Plan shall imply no right of
continued employment with the Company for any Eligible Employee.

                                  XIX. NOTICE

         Any notice which an Eligible Employee or Participant files pursuant to
this Plan shall be in writing and shall be delivered personally or by mail
addressed to the Compensation Committee, c/o Controller at Cellomics, Inc., or
such other person or location as may be specified by the Committee.

                            XX. REPURCHASE OF STOCK

         The Company shall not be required to repurchase from any Participant
shares of Common Stock acquired under this Plan.

               XXI. ADJUSTMENT FOR RECAPITALIZATION, MERGER, ETC.

         The aggregate number of shares of Common Stock which may be purchased
pursuant to purchase rights granted hereunder, the number of shares of Common
Stock covered by each outstanding purchase right, and the purchase price thereof
for each such purchase right shall be appropriately adjusted for any increase or
decrease in the number of outstanding shares of Common Stock resulting from a
stock split or other subdivision or consolidation of shares of Common Stock or
for other capital adjustments or payments of stock dividends or distributions



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or other increases or decreases in the outstanding shares of Common Stock
affected without receipt of consideration of the Company.

         Subject to any required action by the stockholders, if the Company
shall be the surviving corporation in any merger, reorganization or other
business combination, any purchase right granted hereunder shall cover the
securities or other property to which a holder of the number of shares of Common
Stock would have been entitled pursuant to the terms of the merger. A
dissolution or liquidation of the Company or a merger or consolidation in which
the Company is not the surviving entity shall cause every purchase right
outstanding hereunder to terminate.

         The foregoing adjustments and the manner of application of the
foregoing provisions shall be determined by the Committee in its sole
discretion. Any such adjustment shall provide for the elimination of any
fractional share which might otherwise become subject to a purchase right.

                           XXII. AMENDMENT OF THE PLAN


         The Board of Directors may, without the consent of the Participants,
amend the Plan at any time, provided that no such action shall adversely affect
purchase rights theretofore granted hereunder, and provided that no such action
by the Board of Directors, without approval of the Company's stockholders, may:

         (a) increase the total number of shares of Common Stock which may be
purchased by all Participants, except as contemplated in Section XXI;

         (b) change the class of Employees eligible to receive purchase rights
under the Plan;

         (c) decrease the minimum purchase price under Section V;

         (d) extend a Purchase Period hereunder; or

         (e) extend the term of the Plan.

                        XXII. INTERNATIONAL PARTICIPANTS

         With respect to Eligible Employees who reside or work outside the
United States of America, the Committee may, in its sole discretion, amend the
terms of the Plan with respect to such Eligible Employees in order to conform
such terms with the requirements of local law.

                            XXIII. TERM OF THE PLAN

         This Plan shall become effective as of the Effective Date upon its
adoption by the Board of Directors, provided that it is approved at a duly-held
meeting of stockholders of the Company, by an affirmative majority of the total
votes present and voting thereat, within 12 months after the earlier of the
Effective Date or the date of adoption by the Board of Directors. If the Plan is



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not so approved, no Common Stock shall be purchased under the Plan and the
balance of each Participant's Account shall be promptly returned to the
Participant. The Plan shall continue in effect through the December 31st
following the fourth anniversary of the Effective Date, unless terminated prior
thereto pursuant to the next succeeding sentence. The Board of Directors shall
have the right to terminate the Plan at any time, effective as of the next
succeeding Exercise Date. In the event of the expiration of the Plan or its
termination, outstanding purchase rights shall not be affected, except to the
extent provided in Section XV and any remaining balance credited to the Account
of each Participant as of the applicable Exercise Date shall be refunded to each
such Participant.


                              XXIV. GOVERNING LAW

         The validity, constrictions and effect of the Plan, agreements entered
into pursuant to the Plan, and of any rules, regulations, determinations or
decisions made by the Committee relating to the Plan or such agreements, and the
rights of any and all persons having or claiming to have any interest therein or
thereunder, shall be determined exclusively in accordance with applicable
federal laws and the laws of the state of Delaware, without regard to its
conflict of laws principles.







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