-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 N7T93/Ic7FKRWyhs389AzENW25ACH6Z8ONEI3CsHcOV3SmHmf43t9qXgR7stk0Hn
 e0tBfYdESkk8ZUc8+EBoAA==

<SEC-DOCUMENT>9999999995-06-001645.txt : 20060926
<SEC-HEADER>9999999995-06-001645.hdr.sgml : 20060926
<ACCEPTANCE-DATETIME>20060926001513
ACCESSION NUMBER:		9999999995-06-001645
CONFORMED SUBMISSION TYPE:	EFFECT
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20060925
DATE AS OF CHANGE:		20060926
EFFECTIVENESS DATE:		20060925

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KOSAN BIOSCIENCES INC
		CENTRAL INDEX KEY:			0001110206
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
		IRS NUMBER:				943217016
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		EFFECT
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-136617
		FILM NUMBER:		061107590

	BUSINESS ADDRESS:	
		STREET 1:		3832 BAY CENTER PLACE
		CITY:			HAYWARD
		STATE:			CA
		ZIP:			94545
		BUSINESS PHONE:		5107328400

	MAIL ADDRESS:	
		STREET 1:		3832 BAY CENTER PLACE
		CITY:			HAYWARD
		STATE:			CA
		ZIP:			94545
</SEC-HEADER>
<DOCUMENT>
<TYPE>EFFECT
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0101</schemaVersion>

    <submissionType>EFFECT</submissionType>

    <act>33</act>

    <testOrLive>LIVE</testOrLive>

    <effectiveData>
        <finalEffectivenessDispDate>2006-09-25</finalEffectivenessDispDate>
        <form>S-3</form>
        <filer>
            <cik>0001110206</cik>
            <entityName>KOSAN BIOSCIENCES INC</entityName>
            <fileNumber>333-136617</fileNumber>
        </filer>
    </effectiveData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----