- Initial Statement of Beneficial Ownership (3)

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Expires: February 28, 2011 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * BARROWS CRAIG	2. Date of Event Requiring Statement (MM/DD/YYYY) 11/16/2010	3. Issuer Name and Ticker or Trading Symbol IMMUNOGEN INC [IMGN]
(Last)        (First)        (Middle) 22 CHESNUT STREET	4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director                            _____ 10% Owner ___ X ___ Officer (give title below)          _____ Other (specify below) Vice-President,General Counsel /
(Street) SALEM, MA 01970        (City)              (State)              (Zip)	5. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _ X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common stock, $.01 par value	6100	D

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock option (right to buy)	10/3/2008   (1)	10/3/2017	Common stock	50000	$4.50	D
Stock option (right to buy)	6/11/2009   (2)	6/11/2018	Common stock	15000	$3.30	D
Stock option (right to buy)	7/24/2010   (3)	7/24/2019	Common stock	55000	$9.88	D
Stock option (right to buy)	7/23/2011   (4)	7/23/2020	Common stock	40000	$9.14	D

Explanation of Responses:
( 1)	Exercisable as to 12500 shares commencing on 10/3/2008, 12500 shares commencing on 10/3/2009, 12500 shares commencing on 10/3/2010 and 12500 shares commencing on 10/3/2011
( 2)	Exercisable as to 5000 shares commencing on 6/11/2009, 5000 shares commencing on 6/11/2010 and 5000 shares commencing on 6/11/2011
( 3)	Exercisable as to 18333 shares commencing on 7/24/2010, 18334 shares commencing on 7/24/2011 and 18333 shares commencing on 7/24/2012
( 4)	Exercisable as to 13333 shares commencing on 7/23/2011, 13334 shares commencing on 7/23/2012 and 13333 shares commencing on 7/23/2013

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
BARROWS CRAIG 22 CHESNUT STREET SALEM, MA 01970			Vice-President,General Counsel

Signatures
Craig Barrows		11/17/2010
** Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.