S-8

As filed with the Securities and Exchange Commission on May 21, 2004

Registration No. 333-          

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

Under

The Securities Act of 1933

KOSAN BIOSCIENCES INCORPORATED

(Exact name of Registrant as specified in its charter)

Delaware	3832 Bay Center Place Hayward, CA 94545 (510) 732-8400	94-3217016
(State of incorporation)	(Address of principal executive offices)	(I.R.S. Employer Identification Number)

1996 STOCK OPTION PLAN

(Full title of the plan)

Daniel V. Santi, M.D., Ph.D.

Chairman and Chief Executive Officer

Kosan Biosciences Incorporated

3832 Bay Center Place

Hayward, CA 94545

(510) 732-8400

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copy to:

Suzanne Sawochka Hooper, Esq.

COOLEY GODWARD LLP

Five Palo Alto Square

3000 El Camino Real

Palo Alto, CA 94306

(650) 843-5000

CALCULATION OF REGISTRATION FEE

Title of Each Class of Securities to be Registered	Amount to be Registered(1)	Proposed Maximum Offering Price Per Share(2)	Proposed Maximum Aggregate Offering Price(2)	Amount of Registration Fee
Stock options and common stock (par value $.001 per share)	1,000,000 shares	$12.16	$12,160,000	$1,540.67

(1) Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the “Securities Act”), this registration statement shall also cover any additional shares of Kosan’s common stock that become issuable under the 1996 Stock Option Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without Kosan’s receipt of consideration that results in an increase in the number of Kosan’s outstanding shares of common stock.

(2) Estimated solely for the purpose of calculating the amount of the registration fee pursuant to Rule 457(c) and (h)(l) under the Securities Act. The offering price per share and aggregate offering price for the unissued stock options and common stock are based upon the average of the high and low prices of Kosan’s common stock as reported on the Nasdaq National Market on May 20, 2004.

EXPLANATORY NOTE

This Registration Statement on Form S-8 is being filed for the purpose of registering an additional 1,000,000 shares of common stock of Kosan Biosciences Incorporated (“Kosan”) to be issued pursuant to options under Kosan’s 1996 Stock Option Plan, as amended.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The contents of the Registration Statement on Form S-8 (relating to the 1996 Stock Option Plan, 2000 Employee Stock Purchase Plan and 2000 Non-Employee Director Stock Option Plan) File No. 333-47758, the Registration Statements on Form S-8 (relating to the 1996 Stock Option Plan) File Nos. 333-63534 and 333-96669 and the Registration Statement on Form S-8 (relating to the 1996 Stock Option Plan and 2000 Employee Stock Purchase Plan) File No. 333-108502, previously filed with the Securities and Exchange Commission on October 11, 2000, June 21, 2001, July 18, 2002 and September 4, 2003, respectively, are incorporated by reference herein.

EXHIBITS

Exhibit Number	Description
4.1(1)	Amended and Restated Certificate of Incorporation of Registrant, as amended to date.
4.2(2)	Amended and Restated Bylaws of Registrant.
4.3(3)	Specimen of Common Stock Certificate.
5.1	Opinion of Cooley Godward LLP.
23.1	Consent of Ernst & Young LLP, Independent Auditors.
23.2	Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.
24.1	Power of Attorney (contained on the signature page).
99.1(3)	1996 Stock Option Plan, as amended.

(1) Incorporated herein by reference to an exhibit to the Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2001.

(2) Incorporated herein by reference to an exhibit to the Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2003.

(3) Incorporated herein by reference to an exhibit to the Registrant’s Statement on Form S-1, as amended (No. 333-33732), was declared effective on October 4, 2000.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Hayward, State of California, on May 20, 2004.

KOSAN BIOSCIENCES INCORPORATED
By:	/s/    Daniel V. Santi
	Daniel V. Santi, M.D., Ph.D. Chairman and Chief Executive Officer

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Daniel V. Santi and Susan M. Kanaya, and each or any one of them, his or her true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his or her substitutes or substitute, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed on May 20, 2004 by the following persons in the capacities indicated:

Signature	Title	Date
/s/    Daniel V. Santi         Daniel V. Santi, M.D., Ph.D.	Chief Executive Officer and Chairman of the Board of Directors (Principal Executive Officer)	May 20, 2004
/s/    Susan M. Kanaya         Susan M. Kanaya	Senior Vice President, Finance, Chief Financial Officer and Secretary (Principal Financial and Accounting Officer)	May 20, 2004
/s/    Bruce Chabner         Bruce Chabner, M.D.	Director	May 20, 2004
/s/    Peter Davis         Peter Davis, Ph.D.	Director	May 20, 2004

/s/    Jean Deleage         Jean Deleage, Ph.D.	Director	May 20, 2004
/s/    Charles Homcy         Charles Homcy, M.D.	Director	May 20, 2004
/s/    Chaitan Khosla         Chaitan Khosla, Ph.D.	Director	May 20, 2004
/s/    Christopher Walsh         Christopher Walsh, Ph.D.	Director	May 20, 2004

INDEX TO EXHIBITS

Exhibit Number	Description
4.1(1)	Amended and Restated Certificate of Incorporation of Registrant, as amended to date.
4.2(2)	Amended and Restated Bylaws of Registrant.
4.3(3)	Specimen of Stock Certificate.
5.1	Opinion of Cooley Godward LLP.
23.1	Consent of Ernst & Young LLP, Independent Auditors.
23.2	Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.
24.1	Power of Attorney (contained on the signature page).
99.1(3)	1996 Stock Option Plan, as amended.

(1) Incorporated herein by reference to an exhibit to the Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2001.

(2) Incorporated herein by reference to an exhibit to the Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2003.

(3) Incorporated herein by reference to an exhibit to the Registrant’s Statement on Form S-1, as amended (No. 333-33732), was declared effective on October 4, 2000.

EX-5.1

EXHIBIT 5.1

May 20, 2004

Kosan Biosciences Incorporated

3832 Bay Center Place

Hayward, CA 94545

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection with the filing by Kosan Biosciences Incorporated (the “Company”) of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission covering the offering of up to 1,000,000 shares (the “Shares”) of the Company’s common stock, $.001 par value, pursuant to the Company’s 1996 Stock Option Plan, as amended (the “1996 Plan”).

In connection with this opinion, we have examined the Registration Statement and related Prospectus, your Amended and Restated Certificate of Incorporation and Bylaws and such other documents, records, certificates, memoranda and other instruments as we deem necessary as a basis for this opinion. We have assumed the genuineness and authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies thereof and the due execution and delivery of all documents where due execution and delivery are a prerequisite to the effectiveness thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the 1996 Plan, the Registration Statement and the related Prospectus, will be validly issued, fully paid and nonassessable (except as to shares issued pursuant to certain deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

We consent to the filing of this opinion as an exhibit to the Registration Statement.

Very truly yours,

Cooley Godward LLP
By:	/s/    Suzanne Sawochka Hooper
	Suzanne Sawochka Hooper

EX-23.1

EXHIBIT 23.1

CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the 1996 Stock Option Plan of Kosan Biosciences Incorporated of our report dated February 10, 2004, with respect to the financial statements of Kosan Biosciences Incorporated included in its Annual Report (Form 10-K) for the year ended December 31, 2003, filed with the Securities and Exchange Commission.

Palo Alto, California

May 20, 2004