REPLIGEN CORP - Director's Dealing 2008

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REPLIGEN CORP (RGEN)
CIK: 0000730272
Period of Report: 2008-02-14

Reporting Person: WITT DANIEL P (Vice President)

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2008-02-14	Common Stock	M	10000	$1.41	Acquired	99668	Direct
2008-02-14	Common Stock	S	500	$6.34	Disposed	99168	Direct
2008-02-14	Common Stock	S	1700	$6.33	Disposed	97468	Direct
2008-02-14	Common Stock	S	1000	$6.31	Disposed	96468	Direct
2008-02-14	Common Stock	S	7499	$6.30	Disposed	88969	Direct
2008-02-15	Common Stock	S	300	$6.35	Disposed	88669	Direct
2008-02-15	Common Stock	S	300	$6.34	Disposed	88369	Direct
2008-02-15	Common Stock	S	1000	$6.33	Disposed	87369	Direct
2008-02-19	Common Stock	S	378	$6.12	Disposed	86991	Direct
2008-02-19	Common Stock	S	200	$6.11	Disposed	86791	Direct
2008-02-19	Common Stock	S	1457	$6.10	Disposed	85334	Direct

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2008-02-14	Stock Option (Right to Buy)	$1.41	M	10000	Disposed	2008-04-29	Common Stock (10000)	Direct

F1: Sale pursuant to distribution of marital assets in divorce settlement.

F2: 2,000 shares exercisable at each of the following dates: 4/29/1999, 4/29/2000, 4/29/2001, 4/29/2002, 4/29/2003