<PAGE>

                            EXCLUSIVE PATENT LICENSE

                                    AGREEMENT

                                                                    CONFIDENTIAL

         This license agreement (this "Agreement") is effective as of this 1st
day of September, 1997 (the "Effective Date"), by and between the University of
Washington, a public institution of higher education having administrative
offices in Seattle, Washington ("UW") and Rosetta Biosystems, Inc., a company
organized and existing under the laws of the State of Delaware and having a
place of business at 12040 115th Avenue NE, Kirkland, WA 98034 ("Licensee").

1.       PREAMBLE

         1.1 UW has developed and owns or is in possession of certain technology
("INVENTION," defined further below) relating to a novel inkjet technology for
the synthesis of oligonucleotides.

         1.2 UW desires that the INVENTION be used as soon as possible in the
public interest, and to this end desires to transfer the INVENTION to a company
capable of commercially exploiting the INVENTION.

         1.3 Licensee desires, for the purpose of commercial exploitation, to
acquire a license to certain patent rights in and to the INVENTION and to
receive certain technical information relating to the INVENTION.

         1.4      Licensee and UW therefore agree to the terms as set forth
herein.

2.       DEFINITIONS

         2.1 Terms defined in this Definitions Article, and parenthetically
defined elsewhere in this Agreement, shall throughout this Agreement have the
meaning here or there provided. Defined terms may be used in the singular or in
the plural, as sense shall require. Terms defined in this Definition Article
will be printed in capital letters for ease of reference.

         2.2 "INVENTION" shall mean a novel inkjet technotogy for the synthesis
of oligonucleotides on glass or silicon surfaces that provides a proprietary
solution with solvent that allows reagent delivery from the inkjet heads, as
recorded in UW's internal files as [***].

         2.3 "LICENSED PATENTS' shall mean United States Patent applications
listed below and any Patents issued from such, together with all corresponding
foreign patents now issued or issued during the term of this Agreement, which
relate to the INVENTION, and all reissues, reexaminations, extensions,
divisionals, continuations, and continuations-in-part thereof:


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -1-

<PAGE>

<TABLE>
<CAPTION>

         APPLICATION #              COUNTRY          FILING DATE                TITLE
         <S>                        <C>              <C>                        <C>

            08/821,156               U.S.            March 20, 1997            "Solvent for Oligonucleotide Synthesis and Methods
                                                                               of Use"


            in preparation           U.S.                                      "Automated Synthesis of Biopolymer Arrays"


</TABLE>

         2.4 "TECHNICAL INFORMATION" shall mean any technical facts, data, or
advice, written or oral (in the form of information contained in patents and
patent applications, reports, letters, drawings, specifications, testing
procedures, training and operational manuals, bills of materials, photographs
and the like) relating to the INVENTION and owned or in the possession of UW.

         2.5 "LICENSED SUBJECT MATTER" shall mean any subject matter, including
but not limited to products and processes, covered in whole or in part by any
issued, unexpired patent claim or a claim in a pending patent application
contained in the LICENSED PATENTS in the country in which said subject matter is
made, used, or sold.

         2.6 "NET SALES REVENUE" means the amount actually received by Rosetta,
or its assignee, distributor, reseller or other entity in the distribution chain
from an end user for products (but not processes) covered in whole or in part by
any issued, unexpired patent claim or a claim in a pending patent application
contained in the LICENSED PATENTS in the country in which said subject matter is
made, used, or sold, less, at a minimum, returns and customary trade discounts
actually taken, outbound freight, value added, sales or use taxes and custom
duties.

         With respect to COMBINATION PRODUCTS, NET SALES REVENUE shall equal the
amount actually received by Rosetta, or its assignee, distributor, reseller or
other entity in the distribution chain from an end user for products (but not
processes) covered in whole or in part by any issued, unexpired patent claim or
a claim in a pending patent application contained in the LICENSED PATENTS in the
country in which said subject matter is made, used, or sold, multiplied by a
fraction the numerator of which shall be the gross selling price of the LICENSED
SUBJECT MATTER as sold separately and the denominator of which shall be the
gross selling price of the COMBINATION PRODUCT including the LICENSED SUBJECT
MATTER. If there is no established current gross selling price for the LICENSED
SUBJECT MATTER, then for purposes of calculating NET SALES REVENUE, the standard
costs (calculated in accordance with GAAP) of manufacturing of the LICENSED
SUBJECT MATTER shall be used to determine the percentage of sales attributable
to the LICENSED SUBJECT MATTER.

         2.7 "TERRITORY" shall mean worldwide.

         2.8 "SUBLICENSE" shall mean the present, future or contingent transfer
of any License, option, first right to negotiate or other right in the LICENSED
PATENTS OR


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -2-

<PAGE>

LICENSED SUBJECT MATTER in whole or in part.

         2.9 "AGGREGATE ROYALTY" shall mean the total of all royalty obligations
owed by LICENSEE to third parties on NET SALES REVENUE, expressed as a
percentage of NET SALES REVENUE.

         2.10 "COMBINATION PRODUCT' shall mean LICENSED SUBJECT MAT1'ER that is
sold in combination with one or more other products.

3.       GRANT

         3.1 UW hereby grants to Licensee, and Licensee accepts, an exclusive,
royalty-bearing license, with the right to sublicense, under the LICENSED
PATENTS to import, make, have made, use, sell, offer for sale and have sold
LICENSED SUBJECT MATTER in the TERRITORY.

         3.2 The license granted above is subject to a reserved non-exclusive
license in UW to make, have made, and use products, processes, or other subject
matter covered by LICENSED PATENTS for UW's, own research and instructional
purposes in all fields of use independent of funding source.

4.       SUBLICENSING

         4.1 During the term of exclusivity of the license granted in this
Agreement, Licensee shall have the right to grant sublicenses to LICENSED
PATENTS at royalty rates and with other terms and conditions not less favorable
to UW than those required of Licensee by this Agreement.

         4.2 Any and all sublicenses in and to LICENSED PATENTS granted by
Licensee shall be subject to the prior approval of UW, which shall not be
unreasonably withheld.

         4.3 Licensee agrees to forward to UW a copy of any and all fully
executed sublicense agreements pertaining to LICENSED PATENTS within thirty (30)
days of the date of execution of said sublicenses.

5.       TECHNICAL INFORMATION

         5.1 UW, by no later than November 1, 1997, shall provide to Licensee
copies of all patents and patent applications comprising LICENSED PATENTS.

         5.2 UW agrees to disclose to Licensee any other TECHNICAL INFORMATION,
not obtained by UW under conditions of confidentiality, in UW's possession as of
the Effective Date or during the term of this Agreement that in UW's judgment is
necessary or useful to the commercial exploitation of LICENSED PATENTS.

         5.3 LICENSEE agrees to keep any TECHNICAL INFORMATION received from UW
and identified by UW as confidential under conditions of strict secrecy and to
use the same


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -3-

<PAGE>

degree of care Licensee would for its own confidential TECHNICAL INFORMATION,
but no less than reasonable care, to protect UW's confidential TECHNICAL
INFORMATION from disclosure to unauthorized third parties.

6.       DILIGENCE

         6.1 Licensee will use its best efforts during the term of this
Agreement to commercially exploit the LICENSED SUBJECT MATTER through a
thorough, diligent program for bringing the LICENSED SUBJECT MATTER to
commercial market including, as appropriate, through sublicenses; provided,
that such efforts will only be required to the extent the LICENSED SUBJECT
MATTER warrants such efforts in light of then prevailing market conditions,
including the existence of new or more competitive technologies. UW may elect
to terminate or make the licenses set forth in this Agreement non-exclusive
on a field-by-field basis in the event that Licensee fails to fulfill its
diligence obligations with respect to such field, but only after Licensee has
failed to provide reasonable evidence of Licensee's diligence in such field
for ninety (90) days following notice by UW of its intention to terminate or
make such license non-exclusive in such field.

7.       PATENT PROSECUTION AND COST RECOVERY

         7.1 UW shall have sole control over the prosecution of any and all
patent applications, whether pending or not yet filed at the time of execution
of this Agreement, in LICENSED PATENTS, and of the maintenance and other
management of any and all issued patents in LICENSED PATENTS. UW shall keep
Licensee informed of the status of any and all patents and patent applications
comprising LICENSED PATENTS, consult with Licensee regarding the prosecution and
maintenance of the LICENSED PATENTS, and shall provide Licensee with the
opportunity to advise UW on courses of action, filing and prosecution of patent
applications relating to the INVENTIONS and all reissues, reexaminations,
extensions, divisionals, continuations, and continuations-in-part thereof, and
management of patents in LICENSED PATENTS (including the opportunity to appear
before patent examiners together with UW's patent counsel); provided, however,
that UW will have the right to make final determinations with respect to such
prosecution and maintenance.

         7.2 Licensee agrees to reimburse UW for all reasonable fees and costs
relating to the filing and prosecution of patent applications, and maintenance
of LICENSED PATENTS, whether incurred prior to the execution of this Agreement
or during the term of this Agreement Such fees and costs shall not include costs
incurred by the University in the use of its own resources, such as employee
time, and shall not extend to patenting fees and costs incurred by UW after
termination of this Agreement. Licensee agrees to pay invoices for such fees and
costs submitted by UW upon receipt of any such invoice. Alternatively, UW may
choose to have its patent counsel submit invoices directly to Licensee for
payment.

8.       LICENSING FEES; ROYALTIES; EQUITY

         8.1 Licensee shall pay to UW a non-refundable, non-creditable annual
license maintenance fee of [***] due and payable on each anniversary of the
Effective Date.


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -4-

<PAGE>

         8.2 Licensee shall pay to UW an earned royalty of [***] less the
AGGREGATE ROYALTY, down to a minimum of [***], of NET SALES REVENUE.

         8.3 Licensee shall pay to UW a non-refundable annual minimum royalty
of [***] each January 31 following the first commercial sale of LICENSED
SUBJECT MATTER, which minimum royalty shall be fully creditable against the
royalties set forth in Section 8.2 incurred in the twelve (12) months
succeeding such January 31.

         8.4 Licensee shall pay to UW [***] of licensing fees, royalty, and
other income (collectively, "Sublicense Revenue") derived from sublicenses
granted by Licensee in and to LICENSED PATENTS, due and payable within thirty
(30) days of the end of each calendar quarter in which such Sublicense
Revenue is received by Licensee; provided that in no event shall payments
made in exchange for equity or for research funding be included in the
definition of Sublicense Revenue.

          8.5 No multiple royalties shall be payable to UW because any LICENSED
SUBJECT MATTER, its manufacture, use, or sale are or shall be covered by more
than one patent application or issued patent included as part of LICENSED
PATENTS.

          8.6 Upon occurrence of the following events, Licensee will issue
shares of its Common Stock to UW in the following amounts: (a) 90,000 shares
upon execution of this Agreement, (b) 15,000 shares upon issuance of the first
U.S. patent covering the LICENSED SUBJECT MATTER, and (c) 15,000 shares upon the
earlier of (i) first commercial sale by of a product incorporating the LICENSED
SUBJECT MATTER or (ii) one or more sublicenses by Licensee of the LICENSED
SUBJECT MATTER in a transaction or series of transactions where the aggregate
value of the compensation (i.e., up-front license fees, research funding and/or
equity) to Licensee is greater than $1,000,000.

          Where this Agreement provides for the issuance of a specified number
of shares of Licensee's Common Stock at a point after the Effective Date, the
number of and type of shares so specified shall be adjusted from time to time to
take into consideration the occurrence of certain events, including stock
dividends, stock splits, and reverse stock splits.

 9.       PAYMENT AND REPORTS

          9.1 Licensee shall pay earned royalties to UW quarterly within thirty
(30) days of March 31, June 30, September 30, and December 31 of each year.

         9.2 With each payment, Licensee shall include a report setting forth
such particulars of the business conducted by Licensee and any sublicensees
during the preceding calendar quarter as shall be pertinent to royalty
accounting as specified in this Agreement. The report shall include at least (a)
the number of units of LICENSED SUBJECT MATTER manufactured, used, or sold; (b)
gross amounts billed or invoiced for LICENSED SUBJECT MATTER; (c) names and.
addresses of any and all sublicensees; (d) discounts and allowances; and (e)
calculation of total royalties due UW.


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -5-

<PAGE>

          9.3 Until Licensee or any sublicensee engages in commercial use or
sale of LICENSED SUBJECT MATTER, Licensee shall prepare and submit to UW within
thirty (30) days of June 30 and December 31 of each year a report regarding the
progress of Licensee and any sublicensees in developing LICENSED SUBJECT MA1TER
for commercial exploitation. Said report shall include such particulars as are
necessary to demonstrate compliance with diligence obligations set forth in the
Diligence Article of this Agreement.

         9.4 On or before the ninetieth (90th) day following the close of
Licensee's fiscal year, Licensee shall provide UW with Licensee's certified
financial statements for the preceding fiscal year, including, at a minimum, a
Balance Sheet and an Operating Statement

         9.5 All payments required under this Agreement shall be made in U.S.
dollars by check or money order payable to the University of Washington, and
delivered to UW as specified in this Agreement.

         9.6 Licensee agrees to pay a late fee for any overdue payment due UW
under terms of this Agreement. The late fee shall be computed as [***] of the
outstanding, unpaid balance. The payment of such a late fee shall not
foreclose or limit UW from exercising any other rights it may have as a
consequence of the lateness of any payment.

10.      RECORD KEEPING

         10.1 Licensee shall keep complete and accurate records and books of
account containing all information necessary for the computation and
verification of the amounts to be paid hereunder. Licensee shall keep these
records and books for a period of three (3) years following the end of the
accounting period to which the information pertains.

         10.2 Licensee agrees, at the request of UW with reasonable prior
notice, to permit one or more accountants selected by UW ("Accountant") to have
access to Licensee's records and books of account during ordinary working hours
to audit with respect to any payment period ending prior to such request, the
correctness of any report or payment made under this Agreement, or to obtain
information as to the payments due for any such period in the case of failure of
the Licensee to report or make payment pursuant to the terms of this Agreement.

         10.3 The Accountant shall not disclose to UW any information relating
to the business of Licensee except that which is necessary to inform UW of: (a)
the accuracy or inaccuracy of Licensee's reports and payments; (b) compliance or
noncompliance by Licensee with the terms and conditions of this Agreement, and
(c) the extent of any inaccuracy or noncompliance.

         10.4 Should the Accountant believe there is an inaccuracy in any of the
Licensee's payments or noncompliance by the Licensee with any of such terms and
conditions, the Accountant shall have the right to make and retain copies
(including photocopies) of any pertinent portions of the records and books of
account.

         10.5 In the event that Licensee's royalties calculated for any
semi-annual period are under reported by more than [***], the costs
of any audit and review initiated by UW


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -6-

<PAGE>

will be borne by Licensee; but, otherwise, UW shall bear the costs of any audit
initiated by UW.

11.      THIS SECTION INTENTIONALLY LEFT BLANK

12.      TERM AND TERMINATION OF AGREEMENT

         12.1 This Agreement shall be in full force and effect commencing on the
Effective Date and shall remain in effect for twenty (20) years or until the
expiration of the last RENI~INING LICENSED PATENTS, whichever is later, unless
the Agreement is otherwise terminated pursuant to the terms and conditions of
this Agreement.

         12.2 If Licensee breaches any material obligation imposed by this
Agreement (other than the obligations set forth in Section 6 which are governed
by the termination provisions set forth in Section 6) then UW may, at its
option, send a written notice that it intends to terminate the license granted
by this Agreement. If Licensee does not cure the breach within thirty (30) days
from the notice date, then UW shall have the right to terminate this Agreement.

         12.3 UW shall have the right to terminate this Agreement and the
license granted to Licensee hereinabove, effective immediately upon prior
written notice of termination to Licensee in the event that (a) Licensee seeks
liquidation, reorganization, dissolution or winding-up of itself, is insolvent
or evidence exists as to its insolvency, or Licensee makes any general
assignment for the benefit of its creditors; (b) a petition is filed by or
against Licensee, or any proceeding is initiated by or against Licensee, or any
proceeding is initiated against Licensee as a debtor, under any bankruptcy or
insolvency law, unless the laws then in effect void the effectiveness of this
provision; or (c) a receiver, trustee, or any similar officer is appointed to
take possession, custody, or control of all or any part of Licensee's assets or
property, then UW may, at its option, send a written notice that it intends to
terminate the license granted by this Agreement.

         12.4 Licensee shall have a right to terminate this Agreement with or
without cause, upon ninety (90) days prior written notice to UW.

         12.5 The provisions under which this Agreement may be terminated shall
be in addition to any and all other legal remedies which either party may have
for the enforcement of any and all terms hereof, and do not in any way limit any
other legal remedy such party may have.

         12.6 Termination of this Agreement shall terminate all rights and
licenses granted to Licensee relating to LICENSED PATENTS.

         12.7 Upon termination of this Agreement, any and all existing
SUBLICENSE agreement shall be immediately assigned to UW and UW agrees to
maintain such SUBLICENSE agreement in full force to the extent that UW is
capable of performing as a licensor in place of Licensee.

         12.8 Termination by UW or Licensee under the options set forth in this
Agreement


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -7-

<PAGE>

shall not relieve Licensee from any financial obligation to UW accruing prior to
or after termination or from performing according to any and all other
provisions of this Agreement expressly agreed to survive termination.

         12.9 In the event that there remain no valid, enforceable, and
infringed LICENSED PATENTS, Licensee and any sublicensees shall have no further
obligation to pay royalties therein or to account to UW therefor.

13.      NOTICES

         13.1 Any notice or other communication required or permitted to be
given by either party hereto shall be deemed to have been properly given and be
effective upon the date of delivery if delivered in writing to the respective
addresses set forth below, or to such other address as either party shall
designate by written notice given to the other party. If notice or other
communication is given by facsimile transmission, said notice shall be confirmed
by prompt delivery of the hard copy original.

         13.2 All correspondence regarding this Agreement should be addressed as
follows.

      In the case of Licensee:

                Postal Address:   Rosetta BioSystems, Inc.
                                  12040 115th Avenue NE
                                  Suite 210
                                  Kirkland, WA 98034
                                                  Attn: John King

                with a copy to:   Venture Law Group
                                  4750 Carillon Point
                                  Kirkland, WA 98033
                                  Attn: William W. Ericson
                                  Facsimile (425) 739-8750

      In the case of UW:

                Postal Address:   University of Washington
                                  Director of Technology Transfer
                                  Office of Technology Transfer, Box 354810
                                  Seattle, WA 98195
                                  USA

                Street Address:   University of Washington
                                  Director of Technology Transfer
                                  Office of Technology Transfer
                                  1101 N.E. 45th Street, Suite 200
                                  Seattle, WA 98105-6099


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -8-

<PAGE>

                                  USA
                                  Facsimile: (206) 685-4767

14.      PROPRIETARY RIGHTS. Licensee will not, by performance under this
Agreement, obtain any ownership interest in LICENSED PATENTS or any other
proprietary rights or information of UW, its officers, inventors, employees,
students, or agents.

15.      PATENT MARKING. Licensee shall mark, and shall require any sublicensee
to mark, any and all material forms of LICENSED SUBJECT MATTER or packaging
pertaining thereto made and sold by Licensee (and/or by its sublicensees) in the
United States with an appropriate patent marking identifying the pendency of any
U.S. patent application and/or any issued U.S. or foreign patent forming any
part of LICENSED PATENTS. All LICENSED SUBJECT MATTER shipped to or sold in
other countries shall be marked in such a manner as to provide constructive
notice to potential infringers pursuant to the patent laws and practice of the
country of manufacture or sale.

16.      PATENT INFRINGEMENT

          16.1 Each party shall promptly inform the other party of any alleged
infringement of LICENSED PATENTS by a third party, and provide any available
evidence thereof.

          16.2 During the term of exclusivity of the license granted hereunder,
and subject to UW's written approval (such approval not to be untimely or
unreasonably withheld), Licensee shall have the first right to settle any
alleged infringement of LICENSED PATENTS by securing cessation of the
infringement, instituting suit against the infringer, or entering into a
sublicensing agreement in and to relevant patents in LICENSED PATENTS. To enjoy
said first right, Licensee must initiate bona fide action to settle any alleged
infringement within ninety (90) days of receiving UW's approval. After Licensee
has recovered its reasonable attorney's fees and other expenses directly related
to any action, suit, or settlement for infringement of LICENSED PATENTS, UW and
License shall divide any remaining damages, awards, or settlement proceeds in
the following manner:

                           UW          twenty-five percent (25%)
                           Licensee    seventy-five percent (75%)

provided, however, that any payment by an alleged infringer as consideration for
the grant of a sublicense shall be handled according to the royalty provisions
for sublicenses set forth in this Agreement.

          16.3 If Licensee chooses to institute suit against an alleged
infringer during the term of exclusivity as provided in this Agreement, Licensee
may do so in UW's name (if required by law, otherwise, in Licensee's name) but
at Licensee's sole expense, and UW shall, but at Licensee's expense for UW's
direct associated expenses, fully and promptly cooperate and assist Licensee in
connection with any such suit.

         16.4 If Licensee fails, within ninety (90) days of receiving UW's
approval, to secure


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -9-

<PAGE>

cessation of the infringement, institute suit against the infringer, or provide
to UW satisfactory evidence that Licensee is engaged in bona fide negotiation
for the acceptance by infringer of a sublicense in and to relevant patents in
LICENSED PATENTS, UW upon written notice to Licensee may assume full right and
responsibility to secure cessation of the infringement, institute suit against
the infringer, or secure acceptance of a sublicense from Licensee in and to
relevant patents in LICENSED PATENTS, approval for which sublicense Licensee
shall not unreasonably withhold.

          16.5 If UW in accordance with the terms and conditions of this
Agreement chooses to institute suit against an alleged infringer, UW may bring
such suit in its own name (or, if required by law, in its and Licensee's name)
and at its own expense, and Licensee shall, but at UW's expense for Licensee's
direct associated expenses, fully and promptly cooperate and assist UW in
connection with any such suit. Any and all damages, awards, or settlement
proceeds arising from such a UW-initiated action shall be UW's.

          16.6 Neither Licensee nor UW is obligated under this Agreement to
institute a suit against an alleged infringer of LICENSED PATENTS.

17.      PATENT VALIDITY

         17.1 If any claim challenging the validity or enforceability of any of
LICENSED PATENTS shall be brought against Licensee, Licensee shall promptly
notify UW. UW, at its option, shall have the right, within thirty (30) days
after notification-by Licensee of such action, to intervene and take over the
sole defense of the claim at UW's expense.

          17.2 If Licensee challenges the validity or enforceability of any of
LICENSED PATENTS, Licensee agrees not to suspend any payments due UW until such
time as that patent in LICENSED PATENTS is determined to be invalid or
enforceable by final judgment of a court of competent jurisdiction from which no
appeal can be or is taken.

18.      USE OF NAMES. Nothing contained in this Agreement shall be construed as
conferring any right to use in advertising, publicity or other promotional
activities any name, trade name, trademark or other designation of a party
hereto including any contraction, abbreviation or simulation of any of the
foregoing, unless the express written permission of the other party has been
obtained. Licensee hereby expressly agrees not to use the name "University of
Washington" without prior written approval from UW.

19.      REPRESENTATION AND WARRANTIES

         19.1 UW represents and warrants that it has the right to grant the
license in and to LICENSED PATENTS and disclose the TECHNICAL INFORMATION set
forth in this Agreement.

         19.2     Nothing in this Agreement shall be construed as:

                   (a) A representation or warranty by UW as to the
patentability, validity,


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -10-

<PAGE>

scope, or usefulness of LICENSED PATENTS; or

                   (b) A representation or warranty by UW that anything made,
used, sold, or otherwise disposed of under any license granted in this Agreement
is or will be free from infringement of patents or other proprietary rights not
included in LICENSED PATENTS.

          19.3 UW EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES, WHETHER EXPRESS OR
IMPLIED, PERTAINING TO THE MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
OF THE INVENTION, LICENSED SUBJECT MATTER, TECHNICAL INFORMATION, OR ANYTHING
ELSE LICENSED, DISCLOSED, OR OTHERWISE PROVIDED TO LICENSEE UNDER THIS
AGREEMENT. UW'S TOTAL LIABILITY UNDER THIS AGREEMENT IS LIMITED TO THE COSTS AND
FEES PAID TO UW UNDER THIS AGREEMENT.

20.      INDEMNIFICATION. Licensee agrees to indemnify, hold harmless and
defend UW, its officers, inventors, employees, students, and agents, against any
and all claims, suits, losses, damages, costs, fees and expenses resulting from
or arising out of exercise of this Agreement including, but not limited to, any
damages, losses or liabilities whatsoever with respect to death or injury to any
person and damage to any property arising from the possession, use, or operation
of LICENSED SUBJECT MATTER by Licensee or its sublicensees or any customers,
users, or others affected by LICENSED SUBJECT MATTER in any manner whatsoever.
Such indemnification shall not apply to acts or omission by UW, its employees,
agents, successors or assigns. This indemnification clause shall survive the
termination of this Agreement.

21.      APPLICABLE LAWS

          21.1 Licensee agrees to abide by all applicable federal, state, and
local laws and regulations pertaining to the management and commercial
deployment of LICENSED SUBJECT MATTER under this Agreement.

          21.2 LICENSED SUBJECT MATTER may be subject to restrictions concerning
the export of products or technical data from the United States. Accordingly,
Licensee agrees that Licensee shall not export or re-export, directly or
indirectly, any LICENSED SUBJECT MATTER to any country for which the United
States Government or other competent authority at the time of export requires an
export license or other approval, without first obtaining such license or
approval from the appropriate governmental authority.

          21.3 If any dispute shall arise under this Agreement, other than a
bona fide dispute concerning the validity and/or scope of LICENSED PATENTS, the
prevailing party shall be entitled to its reasonable attorney's fees and costs
of litigation and appeal.

22.      NON-BINDING MEDIATION; LITIGATION.

          22.1 Any and all disputes arising between the parties relating to the
making or performance of this Agreement shall be resolved in the following order
of preference: (i) by good faith negotiation between representatives of UW and
Licensee who have authority to fully and


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -11-

<PAGE>

finally resolve the dispute; (ii) if necessary, by non-binding mediation at a
location acceptable to both parties using a neutral mediator having experience
with the industry in accordance with the Rules of the Center for Public
Resources (with the costs therefor shared equally); or (iii) as a last resort
only, by litigation, provided that any suit, action, or proceeding arising out
of or relating to this Agreement shall be decided in King County, Washington.

          22.2 Nothing herein shall preclude either party from taking whatever
actions in equity are necessary to prevent immediate, irreparable harm to its
interests. Otherwise, the procedures set forth in this Section 22 are exclusive
and shall be fully exhausted prior to the initiation of any litigation.

          22.3 Any questions, claims, disputes, remedies or procedural matters
shall be governed exclusively by the laws of the State of Washington, without
regard to the principles of conflicts of law.

23.      GENERAL

          23.1 If any provision of this Agreement shall be held to be invalid,
illegal or unenforceable, the validity, legality and enforceability of the
remaining provisions shall not be in any way affected or impaired thereby.

          23.2 No omission or delay of either party hereto in requiring due and
punctual fulfillment of the obligations of any other party hereto shall be
deemed to constitute a waiver by such party of its rights to require such due
and punctual fulfillment, or of any other of its remedies hereunder.

          23.3 No amendment or modification hereof shall be valid or binding
upon the parties unless it is made in writing, cites this Agreement, and signed
by duly authorized representatives of UW and Licensee.

                   23.4 The headings of the several sections of this Agreement
are inserted for convenience and reference only, and are not intended to be a
part of or to affect the meaning or interpretation of this Agreement

                   23.5 This Agreement embodies the entire understanding of the
parties and supersedes all previous communications, representations, or
understandings, either oral or written, between the parties relating to the
subject matter hereof.

24.      ASSIGNMENT.

                   24.1 Assignment by Licensee. Licensee may not assign, or make
any other transfer with the effect of an assignment, of all of its rights,
privileges, obligations, and duties under this Agreement to any third party,
without the prior written consent of UW, which consent shall not be unreasonably
withheld provided, however, Licensee may make an assignment


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -12-

<PAGE>

without consent if such assignment is to an Affiliate or is a part of the sale
of the entire business of Licensee or of that part of the business involving
substantially all of the LICENSED SUBJECT MATTER. Licensee shall give UW prior
written notice of an assignment which requires the consent of UW. UW will
respond in writing within fifteen (15) days of receipt of the notice and the
absence of any response within the time period shall constitute approval.
Licensee shall give UW written notice of an assignment which does not require
UW's consent within fifteen (15) days of such assignment.

                   24.2 Assignment by UW. UW may not assign, or make any other
transfer with the effect of an assignment, of all of its rights, privileges,
obligations, and duties under this Agreement to any third party, without the
prior written consent of Licensee, which consent shall not be unreasonably
withheld. Licensee will respond in writing within fifteen (15) days of receipt
of the notice and the absence of any response within the time period shall
constitute approval.


                            [SIGNATURE PAGE FOLLOWS]


*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


                                      -13-

<PAGE>

         IN WITNESS WHEREOF, UW and Licensee have executed this Agreement, in
duplicate originals but collectively evidencing only a single contract, by their
respective duly authorized officers, on the dates hereinafter written.

LICENSEE                                             UNIVERSITY OF WASHINGTON


By: /s/: John J. King, II                            By: /s/: DC Miller
   --------------------------------                      ---------------------
Name: John J. King, II                               Name: DC Miller
      -----------------------------                        -------------------
Title: Sr. Vice President & COO                      Title: Director
       ----------------------------                         ------------------
Date: 9/4/97                                         Date: Sept. 4, 1997
      -----------------------------                        -------------------

UNIVERSITY OF WASHINGTON PERSONNEL:


The below-named personnel understand and concur with this Agreement.

By: /s/: Alan Blanchard                              By:
   --------------------------------                      ---------------------
Name: Alan Blanchard                                 Name:
      -----------------------------                        -------------------
Title: Senior Fellow                                 Title:
       ----------------------------                         ------------------
Date: 5-Sept.-97                                     Date:
      -----------------------------                        -------------------



*  Material has been omitted pursuant to a request for confidential treatment,
   and such material has been filed separately with the SEC.


<PAGE>
                                                                EXHIBIT 10.19


              AMENDMENT NO. 1 TO EXCLUSIVE PATENT LICENSE AGREEMENT

                          Dated as of January 28, 1998

         UNIVERSITY OF WASHINGTON (herein called "UW"), a public institution of
higher education having administrative offices in Seattle, Washington, and
ROSETTA INPHARMATICS, INC., (herein called "LICENSEE"), formerly known as
Rosetta Biosystems, Inc., a company organized and existing under the laws of the
State of Delaware and having a place of business at 12040-115th Avenue
Northeast, Kirkland, Washington 98034, hereby agree, effective January 28, 1998,
to amend and revise the Exclusive Patent License Agreement (the "AGREEMENT") by
and between UW and Licensee dated as of September 1, 1997, as set forth below.

         1.          On page 2, Paragraph 2.3:

             (a) under the column headed "Application #", replace "in
                preparation" with "to be assigned (attorney docket no.
                P-UW-2328)";

             (b) under the column headed "Filing Date", replace the blank space
                with [***];

             (c) under the column headed "Title", replace "Automated Synthesis
                of Biopolymer Arrays" with [***]; and

             (d) add a new column entitled "Inventor", and under this new
                column, insert the name [***] in the respective
                row corresponding to each listed application.

         1.  On page 8, Section 13, Notices, replace "Rosetta Biosystems, Inc."
             with "Rosetta Inpharmatics, Inc."

         2.  All other terms and conditions of the Agreement remain in full
             force and effect.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment
effective as of January 28, 1998.

     ROSETTA INPHARMATICS, INC.      UNIVERSITY OF WASHINGTON

     By: /s/ John J. King, II        By: /s/ Robert C. Miller
        ------------------------        ------------------------
         John J. King, II               Robert C. Miller

     SENIOR VICE PRESIDENT AND       DIRECTOR AND ASSOCIATE VICE PROVOST CHIEF
     OPERATING OFFICER             FOR RESEARCH
     --------------------------    --------------------------------------------
     Title                                Title

     FEBRUARY 3, 1998                   FEBRUARY 18, 1998
     --------------------------         -----------------------------------
     Date                               Date

* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.