Exhibit 4.1  



	NUMBER	 	[SENOMYX®, INC. LOGO]	 	SHARES
	

SNMX	
 	

 	
 	

 
	
INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE	
 	

 	
 	

SEE REVERSE FOR CERTAIN DEFINITIONS

CUSIP 81724Q 10 7
	

This Certifies that	
 	

 
	

 	
 	

SPECIMEN	
 	

 
	

is the record holder of	
 	

 




FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK, $.001 PAR VALUE, OF 


------------Senomyx®, Inc.------------ 


transferable
on the books of the Corporation by the holder hereof in person or by duly authorized attorney upon surrender of this certificate properly endorsed. This certificate is not valid until
countersigned by the Transfer Agent and registered by the Registrar. 



WITNESS
the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers. 


Dated:




	/s/ Harry J. Leonhardt	 	 	 	/s/ Kent Snyder
	

VICE PRESIDENT, GENERAL COUNSEL AND CORPORATE SECRETARY	
 	

[SEAL]	
 	

PRESIDENT AND CHIEF EXECUTIVE OFFICER





COUNTERSIGNED AND REGISTERED:

    MELLON INVESTOR SERVICES LLC

        TRANSFER AGENT AND REGISTRAR 


BY



            AUTHORIZED
SIGNATURE 








SenomyxTM, Inc.  


        The Corporation shall furnish without charge to each stockholder who so requests a statement of the powers, designations, preferences and relative, participating,
optional, or other special rights of each class of stock of the Corporation or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights. Such requests shall
be made to the Corporation's Secretary at the principle office of the Corporation. 



        KEEP
THIS CERTIFICATE IN A SAFE PLACE. IF IT IS LOST, STOLEN, OR DESTROYED THE CORPORATION WILL REQUIRE A BOND OF INDEMNITY AS A CONDITION TO THE ISSUANCE OF A REPLACEMENT CERTIFICATE. 


        The
following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or
regulations: 



	TEN COM	—	as tenants in common	UNIF GIFT MIN ACT—	 
	TEN ENT	—	as tenants by the entireties	 	                   Custodian	            
	JT TEN	—	as joint tenants with right of	 	(Cust)                 	  (Minor)
	 	 	survivorship and not as tenants in common	 	under Uniform Gifts to Minors Act
	 	 	 	 	                             

(State)
	

 	

 	

 	

UNIF TRF MIN ACT—	

 
	 	 	 	 	                   Custodian (until age     )	            
	 	 	 	 	(Cust)                 	  (Minor)
	 	 	 	 	under Uniform Transfers to Minors Act
	 	 	 	 	                             

(State)








Additional abbreviations may also be used though not in the above list. 


        For Value Received,      hereby sell(s), assign(s) and transfer(s) unto  



	PLEASE INSERT SOCIAL SECURITY OR OTHER

IDENTIFYING NUMBER OF ASSIGNEE	 
	    
	 






(PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS INCLUDING ZIP CODE OF ASSIGNEE)  











Shares of the common stock represented by the within Certificate, and do hereby irrevocably constitute and appoint 









Attorney to transfer the said stock on the books of the within-named Corporation with full power of substitution in the premises. 



	Dated:               	 	X
	 	 	

	 	 	X
	 	 	

	

 	
 	

 NOTICE: THE SIGNATURE TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE
WHATEVER.
	

Signature(s) Guaranteed

	
 	

 





	By	 	 	 
	 	
	 	 
	THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCK BROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION
PROGRAM), PURSUANT TO S.E.C. RULE 17Ad-15.