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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Iap8aTptTVIevBfwFKmM8uVOcO2L2XApobSZn4tA+VgxOOB1QmLfXxMLf4KUS3hE
 tlKmjjLsMyb6rVb3sGL51A==

<SEC-DOCUMENT>9999999995-10-003097.txt : 20101102
<SEC-HEADER>9999999995-10-003097.hdr.sgml : 20101102
<ACCEPTANCE-DATETIME>20101102001519
ACCESSION NUMBER:		9999999995-10-003097
CONFORMED SUBMISSION TYPE:	EFFECT
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20101101
DATE AS OF CHANGE:		20101102
EFFECTIVENESS DATE:		20101101

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PENWEST PHARMACEUTICALS CO
		CENTRAL INDEX KEY:			0001047188
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				911513032
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		EFFECT
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-153697
		FILM NUMBER:		101156247

	BUSINESS ADDRESS:	
		STREET 1:		2981 ROUTE 22
		STREET 2:		SUITE 2
		CITY:			PATTERSON
		STATE:			NY
		ZIP:			12563-2335
		BUSINESS PHONE:		877-736-9378

	MAIL ADDRESS:	
		STREET 1:		2981 ROUTE 22
		STREET 2:		SUITE 2
		CITY:			PATTERSON
		STATE:			NY
		ZIP:			12563-2335
</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>2010-11-01</finalEffectivenessDispDate>
        <accessionNumber>0001341004-10-001787</accessionNumber>
        <submissionType>POS AM</submissionType>
        <filer>
            <cik>0001047188</cik>
            <entityName>PENWEST PHARMACEUTICALS CO</entityName>
            <fileNumber>333-153697</fileNumber>
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</TEXT>
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