<PAGE>
EXHIBIT 23.1
CONSENT OF INDEPENDENT ACCOUNTANTS
We consent to the incorporation by reference in this Registration Statement
of ImmunoGen, Inc. on Form S-3 to register 4,600,000 shares of common stock of
our report, dated July 28, 2000, except for Note 14 as to which the date is
September 7, 2000 on our audits of the consolidated financial statements of
ImmunoGen, Inc. as of June 30, 2000 and 1999 and for each of the three years in
the period ended June 30, 2000, which report is included in the Company's 2000
Annual Report on Form 10-K.
We also consent to the reference to our Firm in the Registration Statement
under the caption "Experts".
PricewaterhouseCoopers LLP
Boston, Massachusetts
October 17, 2000
