EXHIBIT 10.2


                                                                  April 21, 2005

Mr. Michael Atieh
10 Longwood Road
Morristown, NJ 07920

Re: Employment Agreement

Dear Mike:

     This letter is to confirm our understanding with respect to (i) your future
employment by OSI Pharmaceuticals, Inc. (the "Company"), (ii) your agreement not
to solicit employees or customers of the Company, or any present or future
parent, subsidiary or affiliate of the Company (each, a "Company Affiliate" and
collectively, together with the Company, the "Company", (iii) your agreement to
protect and preserve information and property which is confidential and
proprietary to the Company, and (iv) your agreement with respect to the
ownership of inventions, ideas, copyrights and patents which may be used in the
business of the Company (the terms and conditions agreed to in this letter are
hereinafter referred to as the "Agreement"). In consideration of the mutual
promises and covenants contained in this Agreement, and for other good and
valuable consideration, the receipt and sufficiency of which are hereby mutually
acknowledged, we have agreed as follows:

     1. Employment.

          (a) Subject to the terms and conditions of this Agreement, the Company
     will employ you, and you will be employed by the Company and/or any Company
     Affiliate designated by the Company, initially as Executive Vice President
     and Chief Financial Officer, of the Company reporting to the Chief
     Executive Officer (the "CEO") of the Company. You will have the
     responsibilities, duties and authority customarily performed, undertaken
     and exercised by a person in a similar executive capacity. You will also
     perform such other and/or different services for the Company as may be
     assigned to you from time to time by the CEO. The principal location at
     which you will perform such services will be the Company's headquarters
     located at 58 South Service Road, Melville, New York, although you will be
     available to perform services at any other Company facility and to travel
     as the needs of business may require.

          (b) Devotion to Duties. While you are employed hereunder, you will, to
     the best of your ability, perform faithfully and diligently all duties
     assigned to you pursuant to this Agreement and will devote your full
     business time and energies to the business

     and affairs of the Company. While you are employed hereunder, you will not
     undertake any other employment from any person or entity without the prior
     written consent of the Company.

     2. Term. Except for earlier termination as provided for in Section 4
     hereof, your employment under this Agreement (the "Employment Term") shall
     be for an initial term commencing on May 31, 2005 (the "Effective Date")
     and ending on the third anniversary of the Effective Date (the "Initial
     Term"). Unless written notice is given of an intent not to extend the
     Initial Term or any extension thereof by you or the Company at least 90
     days prior to an anniversary of the Effective Date, the Employment Term
     shall be deemed, as of such 90th day, to have been extended and continue
     until the end of the successive 12-month period unless otherwise terminated
     as provided for in Section 4 hereof. In the event the Company elects not to
     renew the Employment Term, you shall be entitled to the payments and
     benefits set forth in Section 6(c).

     3. Compensation.

          (a) Base Salary. While you are employed hereunder, the Company will
     pay you a base salary at the annual rate of $410,000 (the "Base Salary").
     Your Base Salary will be reviewed on an annual basis each January (or such
     other time as determined by the CEO and/or the Compensation Committee of
     the Board of Directors of the Company (the "Board")), commencing with
     January, 2006. The Base Salary will be payable in equal installments in
     accordance with the Company's payroll practices as in effect from time to
     time. The Company will deduct from each such installment all amounts
     required to be deducted or withheld under applicable law or under any
     employee benefit plan in which you participate.

          (b) Bonus. In addition to the Base Salary, for each fiscal year of the
     Company ending during the Term of the Agreement, beginning with the 2005
     fiscal year, you will be eligible to receive a target bonus of between
     $200,000 - $300,000, determined and payable in accordance with the
     Company's practices applicable to bonuses paid to its executives. The
     Company's bonus system is a discretionary annual performance-based
     incentive bonus system, approved by the Company's Board, and is based upon
     a combination of personal and corporate performance contributing to your
     maximum target. Bonuses are determined in December of each year.

          (c) Equity Compensation.

               (i) Initial Grant. On the Effective Date and pursuant to a
          written stock option agreement (the "Stock Option Agreement") between
          the Company and you under the OSI Pharmaceuticals, Inc. Amended and
          Restated Stock Incentive Plan (the "Plan"), you will be granted a
          non-qualified option (the "Initial Option") to purchase 150,000 shares
          of the Company's common stock, par value, $.01 per share (the "Common
          Stock"). The exercise price will be determined based on the fair
          market value determined at the close of business on the first business
          day of the month after your employment begins. The Initial


                                        2

          Option will have a term of 10 years and will become exercisable with
          respect to 33% of such shares on the first anniversary of the date of
          grant with the remaining shares vesting over the succeeding 48 months
          following the first anniversary of the date of grant on a monthly
          pro-rated basis. Notwithstanding the foregoing, the Initial Option
          shall vest and be fully exercisable upon a Change of Control (as
          hereinafter defined).

               (ii) Future Grants. On each date that annual stock options or
          other equity compensation are granted by the Company to its executive
          management group, so long as you then remain in the employ of the
          Company, the Company will grant to you an option (an "Annual Option")
          to purchase a number of shares of Common Stock to be determined by the
          Compensation Committee of the Board based upon your grade level. The
          exercise price for each Annual Option will be the fair market value
          per share of Common Stock on the date the Annual Option is granted and
          the other terms and conditions of the Annual Option will be as set
          forth in the Plan and Option Agreement accompanying such Annual
          Option. Each Annual Option will have a term of 10 years and will
          become exercisable with respect to 33% of such shares on the first
          anniversary of the date of grant with the remaining shares vesting
          over the succeeding 24 months following the first anniversary of the
          date of grant on a monthly pro-rated basis. Notwithstanding the
          foregoing, each Annual Option shall vest and be fully exercisable upon
          a Change of Control (as hereinafter defined).

               (iii) Restricted Stock Grant On the first business day of the
          month after your employment begins you will be granted a restricted
          stock grant of 15, 000 shares at the closing price of the stock on
          such date. The restrictions will lift on an annual basis at twenty
          percent per year over a period of five years. Notwithstanding the
          foregoing, the Restricted Stock Grant shall vest and be fully
          exercisable upon a Change of Control (as hereinafter defined).

          (d) Vacation. You will be entitled to 22 paid vacation days in each
     calendar year, and paid holidays plus personal days in accordance with the
     Company's policies for its senior executives as in effect from time to
     time.

          (e) Fringe Benefits. In addition to the equity compensation provided
     for herein, you will be entitled to participate in employee benefit plans
     which the Company provides or may establish for the benefit of its senior
     executives generally (for example, term life, disability, medical, dental
     and other insurance, retirement, pension, profit-sharing and similar plans)
     (collectively, the "Fringe Benefits"). Your eligibility to participate in
     the Fringe Benefits and receive benefits thereunder will be subject to the
     plan documents governing such Fringe Benefits. Nothing contained herein
     will require the Company to establish or maintain any Fringe Benefits.

          (f) Relocation. The Company will assist you in your relocation to Long
     Island in accordance with the following:


                                        3

               (i) Relocation Service. American International will assist you in
          your relocation from New Jersey to Long Island.

               (ii) Current Residence. The Company, through American
          International and at your request, will appraise your current
          residence in New Jersey. You will market your home with their
          assistance to try to find a third-party buyer. If the sale price is
          less than the averaged appraisals, OSI will reimburse you the
          difference.

               (iii) Expenses. The Company will reimburse you, either directly
          or through its relocation service, American International, for all
          expenses relating to your relocation from New Jersey to Long Island,
          including, without limitation, expenses relating to packing and moving
          household goods, temporary storage of household goods, closing costs
          (including 2 mortgage points) associated with the purchase of a new
          home on Long Island, sales and closing costs associated with the sale
          of your home in New Jersey, expenses incurred by you and/or your
          family relating to house-hunting trips (including transportation,
          hotel accommodations and meals) and expenses incurred by you and/or
          your family for temporary living accommodations for up to six months
          prior to your move into a new home (including transportation, lease or
          sublease amounts, utilities, hotel or other accommodations, brokers'
          fees). During this 6 month period The Company will pay for a car
          service to bring you to and from Long Island on Mondays and Fridays.
          The Company will continue to pay for your living costs and for a car
          service after the six month period, but any such costs will be fully
          recaptured versus your final relocation costs.

               (iv) Mortgage Assistance. For a period of three years following
          your purchase of a home on Long Island (the "Long Island Home"), the
          Company will pay you a mortgage assistance allowance equal to $50,000
          per annum, payable in equal monthly installments. The foregoing is
          subject to your continued employment with the Company during such
          three-year period. If (A) your employment terminates "without cause"
          (as defined in Section 4(e) hereof), (B) you terminate your employment
          for "good reason" (as defined in Section 4(d) hereof), or (C) upon a
          "Change of Control" (as defined in Section 7 hereof) prior to the end
          of such three-year period, you will continue to receive such mortgage
          assistance allowance on the terms described in this section provided
          that you remain resident in the Long Island Home.

               (v) Lump Sum Payment. In addition to the amounts provided for in
          Sections 3 (f) (iii) and (iv), upon your purchase of the Long Island
          Home, you will receive a one-time lump sum payment equal to $25,000 to
          cover incidental expenses.

               (vii) Pay-Back. If, within 12 months following the Effective
          Date, you terminate your employment with the Company "without good
          reason" (as defined in Section 4(f) hereof), you shall pay back all
          (based upon the date of your termination) of


                                        4

          the amounts paid to you pursuant to Sections 3 (f) (iii), (iv), (v)
          and (vi) (the "Relocation Expenses").

               (viii) Documentation. Reimbursement of the expenses provided for
          in this Section 3(f) shall be made upon presentation of documentation
          reasonably satisfactory to the Company in accordance with the
          Company's policies with respect thereto as in effect from time to
          time. Receipts shall not be required for payment covered under Section
          3 (f) (v).

               (ix) Any amounts paid under this Section 3 (f) deemed to be
          taxable income to you will be grossed up for taxes at the appropriate
          rate.

          (g) Reimbursement of Expenses. Upon presentation of documentation of
     such expenses reasonably satisfactory to the Company, the Company will
     reimburse you for all ordinary and reasonable out-of-pocket business
     expenses that are reasonably incurred by you in furtherance of the
     Company's business in accordance with the Company's policies with respect
     thereto as in effect from time to time.

     4. Termination. The Employment Term shall end upon the earliest of the
     following to occur:

          (a) Your death.

          (b) Upon written notice to you of termination as a result of your
     Permanent Disability. "Permanent Disability" means your inability, by
     reason of any physical or mental impairment, to substantially perform your
     duties and responsibilities hereunder for two or more periods of 90 days
     each in any 360-day period, as determined by a qualified physician with no
     history of prior dealings with you or the Company, as reasonably agreed
     upon by you (or, if you are unable to make such selection, by an adult
     member of your immediate family) and the Company. Such physician's written
     determination of your Permanent Disability shall, upon delivery to the
     Company, be final and conclusive for purposes of this Agreement.

          (c) Your termination by the Company for "cause" as evidenced by, and
     effective upon, delivery by the Company to you of a Notice of Termination
     (as defined in Section 5 below). "Cause" shall mean, for purposes of this
     Agreement, (i) an act of fraud or embezzlement against the Company or an
     unauthorized disclosure of Confidential Information (as defined in Section
     8(a)(iv) hereof) of the Company, in each case which is willful and results
     in material damage to the Company, (ii) any criminal violation of the
     Securities Act of 1933 or the Securities Exchange Act of 1934, (iii) your
     conviction (or a plea of nolo contendere) of any felony, (iv) your gross
     neglect of your duties or your willful and continuing refusal to perform
     your duties, provided you have been given written notice of such neglect or
     refusal and within 30 days have failed to cure such neglect and refusal, or
     (v) your material willful misconduct with respect to the business or
     affairs of the Company.

          (d) Your termination of your employment for "good reason" by
     delivering to the Company a Notice of Termination (as defined in Section 5
     below) not less than 30


                                        5

     days prior to the effective date of such termination. For purposes of this
     Agreement, "good reason" shall mean the occurrence of any of the events
     hereinafter set forth which are not cured by the Company within 30 days
     after the Company has received written notice from you specifying the
     particular events or conditions which constitute "good reason":

          (i)  a material reduction in your duties, title, responsibilities,
               authority, status, or reporting responsibilities unless you have
               previously consented in writing to such reduction (which consent
               may be given or withheld in your sole discretion);

          (ii) a material reduction in your Base Salary or the range of your
               target bonus; or;

          (iii) the Company's requiring you to be based more than 35 miles from
               the Company's current headquarters in Melville, New York or to
               any location for which the average commute from your residence
               exceeds 45 minutes; or

          (iv) change of control (as defined in Section 7 hereof).

          (e) Termination of your employment by the Company "without cause" by
     delivery by the Company to you of a Notice of Termination (as defined in
     Section 5 below) not less than 30 days prior to the effective date of such
     termination. Your termination by the Company shall be considered to be
     "without cause" if you are terminated or dismissed by the Company for
     reasons other than death, permanent disability or for "cause".

          (f) Your termination of your employment "without good reason" by
     delivery by you to the Company of a Notice of Termination (as defined in
     Section 5 below). Your termination of your employment shall be considered
     to be "without good reason" unless you resign for "good reason" (as defined
     in Section 4(d)).

     5. Notice of Termination. Any termination by the Company or by you shall be
     communicated by a written "Notice of Termination" to the other party
     hereto. A "Notice of Termination" shall mean a notice which indicates a
     termination date and the specific termination provision in this Agreement
     relied upon and which sets forth in reasonable detail the facts and
     circumstances claimed to provide a basis for termination under the
     provision so indicated.

     6. Payments Upon Termination.

          (a) Upon termination of your employment for any reason you will become
     entitled to (i) any accrued and unpaid Base Salary up to the date of
     termination, and (ii) any accrued and unpaid vacation pay up to the date of
     termination ((i) and (ii) being collectively referred to as the "Accrued
     Compensation").

          (b) Upon termination of your employment due to death or Permanent
     Disability, in addition to Accrued Compensation, you (or your estate, as
     the case may be)


                                        6

     will become entitled to an amount equal to the bonus that you would have
     been entitled to receive for the fiscal year in which your termination
     occurs had you continued to be employed until the end of such fiscal year,
     multiplied by a fraction (i) the numerator of which is the number of days
     in such fiscal year through the termination date and (ii) the denominator
     or which is 365 (a "Pro-rata Bonus").

          (c) Upon a termination of your employment by the Company "without
     cause" or by you "for good reason" or upon a "Change of Control" (as
     defined in Section 7 hereof), in addition to Accrued Compensation, you will
     become entitled to (i) your Base Salary for 12 months following the date of
     termination, (ii) your Pro-rata Bonus, and (iii) continued coverage for 12
     months following termination under any health and dental program in which
     you were eligible to participate as of the time of termination of your
     employment.

          (d) You shall not be required to mitigate the amount of any payment
     provided for under this Section 6 by seeking other employment or otherwise
     and no payment shall be offset or reduced by the amount of any compensation
     or benefits provided to you in any subsequent employment. The Company's
     obligation to make the payments provided for in this Section 6 and
     otherwise perform its obligations hereunder shall not be affected by any
     circumstances, including, without limitation, set-off, counterclaim,
     recoupment, defense or other claim, right or action which the Company may
     have against you or others.

     7. Change of Control. For purposes of this Agreement, a "Change of Control"
     shall mean the approval by stockholders of the Company of (a) a merger or
     consolidation involving the Company if the stockholders of the Company,
     immediately before such merger or consolidation, do not, as a result of
     such merger or consolidation, directly or indirectly, continue to hold
     greater than 60% of the voting power in the resulting entity, or (b) an
     agreement for the sale or other disposition of all or substantially all of
     the assets of the Company.

     8. Prohibited Activities.

          (a)  Certain Acknowledgements and Agreements.

               (i) We have discussed, and you recognize and acknowledge the
          competitive and proprietary aspects of the business of the Company.

               (ii) You acknowledge that your employment by the Company creates
          a relationship of confidence and trust between the Company and you
          with respect to certain information relating to the business and
          affairs of the Company or applicable to the business of any client,
          customer, consultant, partner, external collaborator or service
          provider of the Company, which may be made known to you by the Company
          or by any client, customer, consultant, partner, external collaborator
          or service provider of the Company, or learned by you during the
          period of your affiliation with the Company.


                                        7

               (iii) You further acknowledge that, while you are employed
          hereunder, the Company will furnish, disclose or make available to you
          Confidential Information (as defined in Section 8 (a) (iv) below)
          related to the business of the Company (whether or not the information
          has commercial value to the Company's business). You also acknowledge
          that such Confidential Information has been developed and will be
          developed by the Company through the expenditure by the Company of
          substantial time, effort and money and that all such Confidential
          Information could be used by you to compete with the Company. You also
          acknowledge that if you become employed or affiliated with any
          competitor of the Company, it is possible that you would disclose
          Confidential Information to such competitor and would use Confidential
          Information, knowingly or unknowingly, on behalf of such competitor.

               (iv) For purposes of this Agreement, "Confidential Information"
          means confidential and proprietary information of the Company, whether
          in written, oral, electronic or other form, including, without
          limitation, systems, processes, formulae, data, functional
          specifications, computer software, programs and displays, know-how,
          improvements, discoveries, inventions, developments, designs,
          techniques, marketing plans, strategies, forecasts, new and proposed
          products and technologies, unpublished financial statements and
          financial information, business plans, budgets, projections, licenses,
          prices, costs, training methods and materials, sales prospects, and
          customer, supplier, manufacturer, collaborator, partner, and client
          lists and any and all intellectual properties, including any
          scientific, technical or trade secrets of the Company or of any third
          party provided to you or the Company under a condition of
          confidentiality, provided that Confidential Information will not
          include information that is in the public domain other than through
          any fault or act by you.

          (b) Covenants. While you are employed hereunder and for a period of
     one year following the termination of your employment hereunder for any
     reason or for no reason, you will not, without the prior written consent of
     the Company:

               (i) Engage, directly or indirectly, for your benefit or the
          benefit of others, in any activity or employment in the performance of
          which any Confidential Information obtained during the course of your
          employment would, by necessity, need to be disclosed by you in order
          to engage in any such activity or employment. This covenant shall not
          be construed to limit in any way your obligation not to use or
          disclose Confidential Information as set forth in Section 9 below.

               (ii) Either individually or on behalf of or through any third
          party, directly or indirectly, solicit, divert or appropriate or
          attempt to solicit, divert or appropriate, any customers of the
          Company or any prospective customers with respect to which the Company
          has developed or made a sales presentation (or similar offering of
          services) for the purpose of directly competing with the Company with
          respect to the Company's "principal marketed products" (i.e., those
          products which are in the first or second detail position) or its
          development


                                        8

          candidates which have material financial significance to the Company
          and which are in Phase III programs; or

               (iii) Either individually or on behalf of or through any third
          party, directly or indirectly, (A) solicit, entice or persuade or
          attempt to solicit, entice or persuade any employees of or consultants
          to the Company to leave the service of the Company for any reason, or
          (B) employ, cause to be employed, or solicit the employment of, any
          employees of or consultants to the Company while any such person is
          providing services to the Company or within six months after any such
          person has ceased providing services to the Company; or

               (iv) Either individually or on behalf of or through any third
          party, directly or indirectly, interfere with, or attempt to interfere
          with, the relations between the Company and any manufacturer or
          supplier to or customer of the Company.

          (c) Reasonableness of Restrictions. You understand that the provisions
     set forth in Section 8(b) are not meant to prevent you from earning a
     living or fostering your career. They are intended, however, to prevent
     competitors of the Company from gaining an unfair advantage from your
     knowledge of Confidential Information. You understand that, by making any
     other employer aware of the provisions set forth in this Section 8, that
     employer can take such action as to avoid your breach of this Section 8.

          (d) Survival of Acknowledgements and Agreements. Your acknowledgements
     and agreements set forth in this Section 8 will survive the termination of
     this Agreement and the termination of your employment hereunder for any
     reason or for no reason.

     9. Protected Information. All Confidential Information shall be the sole
     property of the Company and its assigns. You hereby assign to the Company
     any right you may have or acquire in such Confidential Information. You
     will at all times, both during the period while you are employed hereunder
     and after the termination of this Agreement and the termination of your
     employment hereunder for any reason or for no reason, maintain in
     confidence and will not, without the prior written consent of the Company,
     use, except as required in the course of performance of your duties for the
     Company or by court order, disclose or give to others any Confidential
     Information. In the event you are questioned by anyone not employed by the
     Company or by an employee of or a consultant to the Company not authorized
     to receive Confidential Information, in regard to any Confidential
     Information, or concerning any fact or circumstance relating thereto, you
     will promptly notify the Company. Upon the termination of your employment
     hereunder for any reason or for no reason, or if the Company otherwise
     requests, you will return to the Company all tangible Confidential
     Information and copies thereof (regardless how such Confidential
     Information or copies are maintained). The terms of this Section 9 are in
     addition to, and not in lieu of, any statutory or other contractual or
     legal obligation that you may have relating to the protection of the
     Company's Confidential Information. The terms of this Section 9 will
     survive indefinitely any termination of this Agreement and/or any
     termination of your employment hereunder for any reason or for no reason.


                                        9

     10. Ownership of Ideas, Copyrights and Patents.

          (a) Property of the Company. All ideas, discoveries, creations,
     manuscripts and properties, innovations, improvements, know-how,
     inventions, designs, developments, apparatus, techniques, methods,
     biological processes, cell lines, laboratory notebooks and formulae
     (collectively, the "Inventions") which may be used in the current or
     planned business of the Company or which in any way relates to such
     business, whether patentable, copyrightable or not, which you may conceive,
     reduce to practice or develop while you are employed hereunder (and, if
     based on or related to any Confidential Information, within two years after
     termination of such employment for any reason or for no reason), alone or
     in conjunction with another or others, whether during or out of regular
     business hours, whether or not on the Company's premises or with the use of
     its equipment, and whether at the request or upon the suggestion of the
     Company or otherwise, will be the sole and exclusive property of the
     Company, and that you will not publish any of the Inventions without the
     prior written consent of the Company. Without limiting the foregoing, you
     also acknowledge that all original works of authorship which are made by
     you (solely or jointly with others) within the scope of your employment or
     which relate to the business of the Company and which are protectable by
     copyright are "works made for hire" pursuant to the United States Copyright
     Act (17 U.S.C. Section 101). You will promptly disclose to the Company all
     of the foregoing and you hereby assign to the Company all of your right,
     title and interest in and to all of the foregoing. You further represent
     that, to the best of your knowledge and belief, none of the Inventions will
     violate or infringe upon any right, patent, copyright, trademark or right
     of privacy, or constitute libel or slander against or violate any other
     rights of any person, firm or corporation, and that you will use your best
     efforts to prevent any such violation.

          (b) Cooperation. At any time during your employment hereunder or after
     the termination of your employment hereunder for any reason or for no
     reason, you will cooperate fully with the Company and its attorneys and
     agents in the preparation and filing of all papers and other documents as
     may be required to perfect the Company's rights in and to any of such
     Inventions, including, without limitation, joining in any proceeding to
     obtain letters patent, copyrights, trademarks or other legal rights with
     respect to any such Inventions in the United States and in any and all
     other countries, provided that the Company will bear the expense of such
     proceedings, and that any patent or other legal right so issued to you
     personally will be assigned by you to the Company without charge by you.

          (c) Licensing and Use of Inventions. With respect to any Inventions,
     and work of any similar nature (from any source), whenever created, which
     you have not prepared or originated in the performance of your employment,
     but which you provide to the Company or incorporate in any Company product
     or system, you hereby grant to the Company a royalty-free, fully paid-up,
     non-exclusive, perpetual and irrevocable license throughout the world to
     use, modify, create derivative works from, disclose, publish, translate,
     reproduce, deliver, perform, dispose of, and to authorize others so to do,
     all such Inventions. You will not include in any Inventions you deliver to
     the Company or


                                       10

     use on its behalf, without the prior written approval of the Company, any
     material which is or will be patented, copyrighted or trademarked by you or
     others unless you provide the Company with the written permission of the
     holder of any patent, copyright or trademark owner for the Company to use
     such material in a manner consistent with then-current Company policy.

          (d) Prior Inventions. Listed on Exhibit 10(d) to this Agreement are
     any and all Inventions in which you claim or intend to claim any right,
     title and interest (collectively, "Prior Inventions"), including, without
     limitation, patent, copyright and trademark interests, which to the best of
     your knowledge will be or may be delivered to the Company in the course of
     your employment, or incorporated into any Company product or system. You
     acknowledge that your obligation to disclose such information is ongoing
     while you are employed hereunder.

     11. Records. Upon termination of your employment hereunder for any reason
     or for no reason and at any other time requested by the Company, you will
     deliver to the Company any property of the Company which may be in your
     possession, including products, materials, memoranda, notes, records,
     reports, or other documents or photocopies of the same.

     12. Representations. You hereby represent and warrant to the Company that
     you understand this Agreement, that you enter into this Agreement
     voluntarily and that your employment under this Agreement will not conflict
     with any legal duty owed by you to any other party, or with any agreement
     to which you are a party or by which you are bound, including, without
     limitation, any non-competition or non-solicitation provision contained in
     any such agreement.

     13. General.

          (a) Notices. All notices, requests, consents and other communications
     hereunder which are required to be provided, or which the sender elects to
     provide, in writing, will be addressed to the receiving party's address set
     forth above or to such other address as a party may designate by notice
     hereunder, and will be either (i) delivered by hand, (ii) sent by overnight
     courier, or (iii) sent by registered or certified mail, return receipt
     requested, postage prepaid. All notices, requests, consents and other
     communications hereunder will be deemed to have been given either (i) if by
     hand, at the time of the delivery thereof to the receiving party at the
     address of such party set forth above, (ii) if sent by overnight courier,
     on the next business day following the day such notice is delivered to the
     courier service, or (iii) if sent by registered or certified mail, on the
     fifth business day following the day such mailing is made.

          (b) Entire Agreement. This Agreement, and the other agreements
     specifically referred to herein, embodies the entire agreement and
     understanding between the parties hereto with respect to the subject matter
     hereof and supersedes all prior oral or written agreements and
     understandings relating to the subject matter hereof. No statement,
     representation, warranty, covenant or agreement of any kind not expressly
     set forth in this


                                       11

     Agreement will affect, or be used to interpret, change or restrict, the
     express terms and provisions of this Agreement.

          (c) Modifications and Amendments. The terms and provisions of this
     Agreement may be modified or amended only by written agreement executed by
     the parties hereto.

          (d) Waivers and Consents. The terms and provisions of this Agreement
     may be waived, or consent for the departure therefrom granted, only by
     written document executed by the party entitled to the benefits of such
     terms or provisions. No such waiver or consent will be deemed to be or will
     constitute a waiver or consent with respect to any other terms or
     provisions of this Agreement, whether or not similar. Each such waiver or
     consent will be effective only in the specific instance and for the purpose
     for which it was given, and will not constitute a continuing waiver or
     consent.

          (e) Assignment. The Company may assign its rights and obligations
     hereunder to any person or entity that succeeds to all or substantially all
     of the Company's business or that aspect of the Company's business in which
     you are principally involved or to any Company Affiliate; provided, that
     the Company shall remain responsible for any payments and obligations to
     you to the extent any assignee fails to fulfill such payments and
     obligations. You may not assign your rights and obligations under this
     Agreement without the prior written consent of the Company and any such
     attempted assignment by you without the prior written consent of the
     Company will be void.

          (f) Benefit. All statements, representations, warranties, covenants
     and agreements in this Agreement will be binding on the parties hereto and
     will inure to the benefit of the respective successors and permitted
     assigns of each party hereto. Nothing in this Agreement will be construed
     to create any rights or obligations except between the Company and you,
     except for your obligations to the Company as set forth herein, and no
     person or entity (except for a Company Affiliate as set forth herein) will
     be regarded as a third-party beneficiary of this Agreement.

          (g) Governing Law. This Agreement and the rights and obligations of
     the parties hereunder will be construed in accordance with and governed by
     the laws of the State of New York, without giving effect to the conflict of
     law principles thereof.

          (h) Jurisdiction, Venue and Service of Process. Any legal action or
     proceeding with respect to this Agreement that is not subject to
     arbitration pursuant to Section 14 (i) below will be brought in the courts
     of Suffolk County, New York. By execution and delivery of this Agreement,
     each of the parties hereto accepts for itself and in respect of its
     property, generally and unconditionally, the exclusive jurisdiction of the
     aforesaid courts.

          (i) Arbitration. Any controversy, dispute or claim arising out of or
     in connection with this Agreement, other than a controversy, dispute or
     claim arising under Section 8, 9 or 10 hereof, will be settled by final and
     binding arbitration to be conducted in New York, New York pursuant to the
     national rules for the resolution of employment disputes of the American
     Arbitration Association then in effect. The decision or award in


                                       12

     any such arbitration will be final and binding upon the parties and
     judgment upon such decision or award may be entered in any court of
     competent jurisdiction or application may be made to any such court for
     judicial acceptance of such decision or award and an order of enforcement.
     In the event that any procedural matter is not covered by the aforesaid
     rules, the procedural law of New York will govern. Any disagreement as to
     whether a particular dispute is arbitrable under this Agreement shall
     itself be subject to arbitration in accordance with the procedures set
     forth herein. The fees of the arbitrators shall be paid by the Company.

          (j) WAIVER OF JURY TRIAL. ANY ACTION, DEMAND, CLAIM OR COUNTERCLAIM
     ARISING UNDER OR RELATING TO THIS AGREEMENT THAT IS NOT SUBJECT TO
     ARBITRATION PURSUANT TO SECTION 14(i) ABOVE WILL BE RESOLVED BY A JUDGE
     ALONE AND EACH OF YOU AND THE COMPANY WAIVE ANY RIGHT TO A JURY TRIAL
     THEREOF.

          (k) Severability. The parties intend this Agreement to be enforced as
     written. However, (i) if any portion or provision of this Agreement is to
     any extent declared illegal or unenforceable by a duly authorized court
     having jurisdiction, then the remainder of this Agreement, or the
     application of such portion or provision in circumstances other than those
     as to which it is so declared illegal or unenforceable, will not be
     affected thereby, and each portion and provision of this Agreement will be
     valid and enforceable to the fullest extent permitted by law and (ii) if
     any provision, or part thereof, is held to be unenforceable because of the
     duration of such provision, the geographic area covered thereby, or other
     aspect or scope of such provision, the court making such determination will
     have the power to reduce the duration, geographic area of such provision,
     or other aspect or scope of such provision, and/or to delete specific words
     and phrases ("blue-penciling"), and in its reduced or blue-penciled form,
     such provision will then be enforceable and will be enforced.

          (l) Injunctive Relief. You hereby expressly acknowledge that any
     breach or threatened breach of any of the terms and/or conditions set forth
     in Section 8, 9 or 10 of this Agreement will result in substantial,
     continuing and irreparable injury to the Company. Therefore, in addition to
     any other remedy that may be available to the Company, the Company will be
     entitled to injunctive or other equitable relief by a court of appropriate
     jurisdiction in the event of any breach or threatened breach of the terms
     of Section 8, 9 or 10 of this Agreement. The period during which the
     covenants contained in Section 8 will apply will be extended by any periods
     during which you are found by a court to have been in violation of such
     covenants.

          (m) No Waiver of Rights, Powers and Remedies. No failure or delay by a
     party hereto in exercising any right, power or remedy under this Agreement,
     and no course of dealing between the parties hereto, will operate as a
     waiver of any such right, power or remedy of the party. No single or
     partial exercise of any right, power or remedy under this Agreement by a
     party hereto, nor any abandonment or discontinuance of steps to enforce any
     such right, power or remedy, will preclude such party from any other or
     further exercise thereof or the exercise of any other right, power or
     remedy hereunder. The election of any remedy by a party hereto will not
     constitute a waiver of the right of such party to pursue other available
     remedies. No notice to or demand on a party not expressly required under


                                       13

     this Agreement will entitle the party receiving such notice or demand to
     any other or further notice or demand in similar or other circumstances or
     constitute a waiver of the rights of the party giving such notice or demand
     to any other or further action in any circumstances without such notice or
     demand.

          (n) Counterparts. This Agreement may be executed in two or more
     counterparts, and by different parties hereto on separate counterparts,
     each of which will be deemed an original, but all of which together will
     constitute one and the same instrument.

          (o) Opportunity to Review. You hereby acknowledge that you have had
     adequate opportunity to review these terms and conditions and to reflect
     upon and consider the terms and conditions of this Agreement, and that you
     have had the opportunity to consult with counsel of your own choosing
     regarding such terms. You further acknowledge that you fully understand the
     terms of this Agreement and have voluntarily executed this Agreement.

          (p) Survival of the Company's Obligations. Notwithstanding the
     termination of this agreement pursuant to Section 4, the Company's
     obligation to make payments and provide benefits to you as set forth in
     Section 3 (g) (iv) and Section 6 will remain in effect.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                       14

     If the foregoing accurately sets forth our agreement, please so indicate by
signing and returning to us the enclosed copy of this Agreement.

                                        Very truly yours,

                                        OSI Pharmaceuticals, Inc.


                                        By: /s/
                                            ------------------------------------
                                        Name: Colin Goddard, Ph.D
                                        Title: Chief Executive Officer


Accepted and Approved:


/s/                                     April 21, 2005
- -------------------------------------   Date
Michael Atieh


                                       15

                                  EXHIBIT 10(d)

                                PRIOR INVENTIONS


                                       16