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[Corvas letterhead]



September 23, 1997

William C. Ripka, Ph.D.
10819 Red Rock Drive
San Diego, California  92131

Dear Bill:

This letter sets forth the terms and conditions of our agreement (the 
"Agreement") regarding your retirement from Corvas International, Inc. (the 
"Company").  This Agreement shall supersede any and all previous agreements 
between you and the Company including, but not limited to, that Employment 
Agreement (the "Employment Agreement") dated March 18, 1997, provided, 
however, that the confidentiality agreement attached as Exhibit C to the 
Employment Agreement shall continue in full force and effect.

This Agreement is made and entered into as of the last day either party 
executes this Agreement.  Pursuant to paragraph 13 set forth below, the 
Agreement shall become effective on the eighth day after this Agreement is 
signed by you (the "Effective Date").  You and the Company hereby agree as 
follows:

1.       This Agreement confirms your retirement from the Company and 
resignation of your position as Senior Vice President, Chemical Research, of 
the Company as of September 30, 1997 (the "Separation Date").  

2.       The Company agrees that it will pay you all accrued salary, and all 
accrued and unused vacation benefits earned through the Separation Date, if 
any, subject to standard payroll deductions, withholding taxes and other 
obligations. You are entitled to this payment regardless of whether or not 
you sign this Agreement.

3.       Although the Company has no policy or procedure for providing 
severance benefits, in exchange for the promises and covenants set forth 
herein, and in consideration thereof, the Company will pay you the equivalent 
of twelve months of your base salary in effect as of the Separation Date, 
subject to standard payroll deductions and withholdings.  Half of this amount 
will be paid in a lump sum within fourteen (14) days of the Effective Date of 
this Agreement as defined in paragraph 13, with the rest paid out over the 
next six (6) months.

4.       To the extent provided by the federal COBRA law or, if applicable, 
state insurance laws, and by the Company's current group health insurance 
policies, you will be eligible to continue your health insurance benefits.  
You will be provided with a separate notice of your COBRA rights.  In the 
event that you elect continued coverage under COBRA, the Company, as part of 
this Agreement and in consideration thereof, will reimburse you on a monthly 
basis for the same portion of your COBRA health insurance premium that it 
paid during your employment for one year from the Separation Date.  You will 
continue to be responsible for the same portion of the COBRA health insurance 
premium that you paid during your employment with the Company.

5.       In exchange for the promises and covenants set forth herein, the 
Company agrees that the vesting of each outstanding stock option held by you 
as set forth on Exhibit A attached hereto (the "Stock Options") shall be 
fully accelerated and become immediately exerciseable in full; provided,

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William C. Ripka, Ph.D.
September 23, 1997
Page 2

that in any event, should you choose to exercise your Stock Options, you must 
do so within twenty-four (24) months of the Separation Date as provided in 
Section 3.3(c) of the standard terms and conditions relating to Incentive 
Stock Options attached to and made part of your Incentive Stock Option 
Agreement dated December 4, 1996 (your "Stock Option Agreement").  Your Stock 
Options will terminate twenty-four (24) months after the Separation Date if 
not exercised.  You agree that you otherwise remain bound by the terms and 
conditions of your Stock Option Agreement.  In addition, you understand that, 
pursuant to tax law, your Stock Options will lose potentially favorable tax 
treatment afforded "incentive stock options" if not exercised within three 
(3) months of the Separation Date.

6.       You hereby acknowledge and agree that except as expressly provided 
herein, you will not receive (nor are you entitled to) any additional 
compensation, severance, benefits, shares of Company stock or stock options 
exerciseable for Company stock, notwithstanding any prior agreement to the 
contrary, including the Employment Agreement, after the Separation Date.

7.       You agree that, within ten (10) days of the Separation Date, you 
will submit your final documented expense reimbursement statement reflecting 
all business expenses you incurred through the Separation Date, if any, for 
which you seek reimbursement.  The Company will reimburse you for these 
expenses pursuant to its regular business practice.  You further agree that 
you will not be entitled to any expense reimbursements after the Separation 
Date.

8.       You agree that for one year after the Separation Date, you will not, 
either directly or through others, solicit or attempt to solicit any 
employee, consultant, or independent contractor of the Company to terminate 
his or her relationship with the Company in order to become an employee, 
consultant or independent contractor to or for any other person or entity.

9.       Upon the Separation Date, you agree to return to the Company all 
Company documents (and all copies thereof) and other Company property in your 
possession or your control, including, but not limited to, Company files, 
notes, samples of compounds, drawings, specifications, calculations, 
sequences, data, computer-recorded information, tangible property, including, 
but not limited to, computers, credit cards, entry cards, keys and any other 
materials of any nature pertaining to your work with the Company, and any 
documents or data of any description (or any reproduction of any documents or 
data) containing or pertaining to any proprietary or confidential material of 
the Company.

10.      Both during and after your employment you acknowledge your 
continuing obligations under your Employment Agreement not to use or disclose 
any confidential or proprietary information of the Company without prior 
written authorization from a duly authorized representative of the Company.  
A copy of your Employment Agreement is attached hereto as Exhibit B.

11.      You and the Company agree that neither party will at any time 
disparage the other party, and the other party's officers, directors, 
employees, shareholders and agents, in any manner likely to be harmful to 
them or their business, business reputation or personal reputation; provided 
that each party shall respond accurately and fully to any questions, inquiry 
or request for information when required by legal process.

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William C. Ripka, Ph.D.
September 23, 1997
Page 3

12.      The provisions of this Agreement shall be held in strictest 
confidence by you and the Company and shall not be publicized or disclosed in 
any manner whatsoever;  provided, however, that: (a) you may disclose this 
Agreement, in confidence, to your immediate family; (b) the parties may 
disclose this Agreement in confidence to their respective attorneys, 
accountants, auditors, tax preparers, and financial advisors; (c) the Company 
may disclose this Agreement as necessary to fulfill standard or legally 
required corporate reporting or disclosure requirements; and (d) the parties 
may disclose this Agreement insofar as such disclosure may be necessary to 
enforce its terms or as otherwise required by law.

13.      In exchange for the promises and covenants set forth herein, you 
hereby release, acquit, and forever discharge the Company, its parents and 
subsidiaries, and their officers, directors, agents, servants, employees, 
attorneys, shareholders, partners, successors, assigns, affiliates, 
customers, and clients of and from any and all claims liabilities, demands, 
causes of action, costs, expenses, attorneys' fees, damages, indemnities and 
obligations of every kind and nature, in law, equity, or otherwise, known and 
unknown, suspected and unsuspected, disclosed and undisclosed, arising out of 
or in any way related to agreements, acts or conduct at any time prior to the 
Separation Date, including, but not limited to: all such claims and demands 
directly or indirectly arising  out of or in any way connected with the 
Company's employment of you, the termination of that employment, and the 
Company's performance of its obligations as your former employer; claims or 
demands related to salary, bonuses, commissions, stock, stock options, or any 
other ownership interests in the Company, vacation pay, fringe benefits, 
expense reimbursements, severance pay, or any form of compensation; claims 
pursuant to any federal, state or local law or cause of action including, but 
not limited to, the California Fair Employment and Housing Act, the federal 
Civil Rights Act of 1964, as amended; the federal Age Discrimination in 
Employment Act of 1967, as amended; the federal Americans With Disabilities 
Act; tort law; contract law; wrongful discharge; discrimination; harassment; 
fraud; defamation; emotional distress; and breach of the implied covenant of 
good faith and fair dealing.

         You further acknowledge that you are knowingly and voluntarily 
waiving and releasing any rights you may have under the Age Discrimination in 
Employment Act of 1967 ("ADEA").  You also acknowledge that the consideration 
given for the waiver and release in the preceding paragraphs hereof is in 
addition to anything of value to which you were already entitled.  You hereby 
provide the further acknowledgment that you are advised by this writing, as 
required by the Older Workers Benefit Protection Act, that: (a) your waiver 
and release do not apply to any rights or claims that may arise after the 
Effective Date of this release; (b) you have the right to consult with an 
attorney prior to executing this release (although you may voluntarily choose 
not to do so); (c) you may have at least twenty-one (21) days to consider 
this Agreement (although you may by your own choice execute this release 
earlier); (d) you have seven (7) days following the execution of this release 
to revoke this release; and (e) this Agreement shall not be effective until 
the date upon which the revocation period has expired, therefore making the 
effective date the eighth day after this release is signed by you (the 
"Effective Date").

14.      In giving this release, which includes claims which may be unknown 
to you at present, you hereby acknowledge that you have read and understand 
Section 1542 of the Civil Code of the State of California which reads as 
follows:

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William C. Ripka, Ph.D.
September 23, 1997
Page 4

         A general release does not extend to claims which the 
         creditor does not know or suspect to exist in his favor 
         at the time of executing the release, which if known by 
         him must have materially affected his settlement with 
         the debtor.

         You hereby expressly waive and relinquish all rights and benefits 
under this section and any law or legal principle of similar effect in any 
jurisdiction with respect to claims released hereby.

15.      In the event of any litigation arising out of or relating to this 
Agreement, its breach or enforcement, including an action for declaratory 
relief, the prevailing party in such action or proceeding shall be entitled 
to receive his or its damages, court costs, and all out-of-pocket expenses, 
including attorneys fees.  Such recovery shall include court costs, 
out-of-pocket expenses, and attorneys fees on appeal, if any.

16.      The parties hereto hereby acknowledge that this is a compromise 
settlement of various matters, and that the promised payments in 
consideration of this Agreement shall not be construed to be an admission of 
any liability or obligation by either party to the other party or to any 
other person whomsoever.

17.      This Agreement, including Exhibit A and B, constitutes the complete, 
final and exclusive embodiment of the entire agreement between you and the 
Company with regard to the subject matter hereof.  It is entered into without 
reliance on any promise or representation, written or oral, other than those 
expressly contained herein.  It may not be modified except in a writing 
signed by you and a duly authorized officer of the Company.  Each party has 
carefully read this Agreement, has been afforded the opportunity to be 
advised of its meaning and consequences by his or its respective attorneys, 
and signed the same of his or its free will.

18.      This Agreement shall bind the heirs, personal representatives, 
successors, assigns, executors, and administrators of each party, and inure 
to the benefit of each party, its agents, directors, officers, employees, 
servants, heirs, successors and assigns.

19.      This Agreement shall be deemed to have been entered into and shall 
be construed and enforced in accordance with the laws of the State of 
California as applied to contracts made and to be performed entirely within 
California.

20.      If a court of competent jurisdiction determines that any term or 
provision of this Agreement is invalid or unenforceable, in whole or in part, 
then the remaining terms and provisions hereof shall be unimpaired.  Such 
court will have the authority to modify or replace the invalid or 
unenforceable term or provision with a valid and enforceable term or 
provision that most accurately represents the parties' intention with respect 
to the invalid or unenforceable term or provision.

21.      This Agreement may be executed in two counterparts, each of which 
shall be deemed an original, all of which together shall constitute one and 
the same instrument.

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William C. Ripka, Ph.D.
September 23, 1997
Page 5

Please confirm your assent to the foregoing terms and conditions of our 
Agreement by signing and returning this letter to me. 

Sincerely,

CORVAS INTERNATIONAL, INC.


/s/ RANDALL E. WOODS
-----------------------------
Randall E. Woods
President and Chief Executive Officer


HAVING READ AND REVIEWED THE FOREGOING, I HEREBY AGREE TO AND ACCEPT THE 
TERMS AND CONDITIONS AS STATED ABOVE.

Dated: SEPT. 26, 1997                  /s/ WILLIAM C. RIPKA, Ph.D.
       ---------------                 ------------------------------
                                       William C. Ripka, Ph.D.