As filed with the Securities and Exchange Commission on January 10, 2000
Registration No. 333-48993

SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

POST EFFECTIVE AMENDMENT NO. 1 TO
FORM S-8
REGISTRATION STATEMENT UNDER
THE SECURITIES ACT OF 1933

LEUKOSITE, INC.
(Exact Name of Registrant as Specified in Its Charter)

DELAWARE
(State or Other Jurisdiction of 04-3173859
Incorporation or Organization (I.R.S. Employer Identification No.)

75 SIDNEY STREET, CAMBRIDGE MASSACHUSETTS 02139
(Address of Principal Executive Offices) (Zip Code)

LEUKOSITE, INC. 1997 EMPLOYEE STOCK PURCHASE PLAN
(Full Title of the Plan)

JOHN MARAGANORE
PRESIDENT
LEUKOSITE, INC.
75 SIDNEY STREET
CAMBRIDGE, MA 02139
(Name and Address of Agent For Service)

(617) 679-7000
(Telephone Number, Including Area Code, of Agent For Service)

Copy to:
David E. Redlick, Esq.
Jeffrey A. Stein, Esq.
Hale and Dorr, LLP
60 State Street
Boston, MA 02109

DEREGISTRATION OF COMMON STOCK

On March 31, 1998, LeukoSite, Inc. (the "Company") filed a Registration
Statement on Form S-8, Registration No. 333-48993 (the "Registration
Statement"), for the sale of 150,000 shares of common stock, par value $0.01 per
share of the Company (the "Shares") under the Company's 1997 Employee Stock
Purchase Plan (the "Plan"). On December 22, 1999, the stockholders of the
Company approved and adopted an Agreement and Plan of Merger, dated as of
October 14, 1999, by and among the Company, Millennium Pharmaceuticals, Inc. and
ANM, Inc., a wholly-owned subsidiary of Millennium. Pursuant to the merger
agreement, Millennium assumed the obligations of the Company under the Plan and
the Plan was terminated. This Post-Effective Amendment No. 1 to the Registration
Statement is being filed to deregister all of the unsold shares of common stock
formerly issuable under the plan, constituting 108,670 shares.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on
this 10th day of January, 2000.

LEUKOSITE, INC.

By: /s/ John Maraganore
------------------------------
John Maraganore
President

Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed below by the following persons in
the capacities and on the date indicated.

Signature Title Date
--------- ----- ----

/s/ John Maraganore Chairman of the Board and President January 10, 2000
- ------------------------
John Maraganore (Principal Executive Officer)

/s/ Kevin P. Starr Director (Principal Financial and January 10, 2000
- ------------------------
Kevin P. Starr Accounting Officer)

/s/ Mark J. Levin Director January 10, 2000
- ------------------------
Mark J. Levin