<PAGE>
 
  As filed with the Securities and Exchange Commission on February 25, 1999.
                                        
                                                   Registration No. 333-________
                                                                                
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, DC. 20549
                                        
                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

              Cambridge Technology Partners (Massachusetts), Inc.
             (Exact Name of Registrant as Specified in Its Charter)

           Delaware                                  06-1320610
(State or Other Jurisdiction of                   (I.R.S. Employer
 Incorporation or Organization)                  Identification No.)

                               304 Vassar Street
                         Cambridge, Massachusetts 02139
                                 (617) 374-9800
              (Address of Principal Executive Offices) (Zip Code)
                         _____________________________

              Cambridge Technology Partners (Massachusetts), Inc.
                             1991 Stock Option Plan
                            (Full Title of the Plan)
                         _____________________________

                              Arthur M. Toscanini
                            Chief Financial Officer
              Cambridge Technology Partners (Massachusetts), Inc.
                               304 Vassar Street
                         Cambridge, Massachusetts 02139
                    (Name and Address of Agent For Service)

                                 (617) 374-9800
         (Telephone Number, Including Area Code, of Agent For Service)
                         _____________________________

                                    Copy to:
                                        
                             Steven C. Browne, Esq.
                        Testa, Hurwitz & Thibeault, LLP
                       High Street Tower, 125 High Street
                          Boston, Massachusetts 02110
                                 (617) 248-7000
                                        
================================================================================

                        CALCULATION OF REGISTRATION FEE



<TABLE>
<CAPTION>
Title of                                 Proposed Maximum      Proposed Maximum
Securities To Be      Amount To Be           Offering             Aggregate               Amount of 
Registered            Registered          Price Per Share       Offering Price         Registration Fee
----------------      ----------------   ----------------     ------------------       ----------------
<S>                   <C>                <C>                  <C>                      <C>
 
Common Stock            186,929 shares          $26.44 (1)     $ 4,942,402.76                 $ 1,373.99
(Par Value $.01)        715,120 shares          $15.50 (2)     $11,084,360.00                 $ 3,081.45
                      2,317,880 shares          $22.50 (3)     $52,152,300.00                 $14,498.34
                        780,071 shares          $29.47 (4)     $22,988,692.37                 $ 6,390.86 
                      ----------------                         --------------                 ----------
TOTAL:                4,000,000 shares                         $91,167,755.13                  25,344.64
                      ================                         ==============                 ==========
Preferred Stock
Purchase Rights(5)            -                      -                  -                         -
</TABLE>
================================================================================

(1)  All of such shares are issuable upon the exercise of outstanding options to
     purchase an aggregate of 186,929 shares at an exercise price of $26.44 per
     share.  Pursuant to Rule 457(h)(1) of the Securities Act of 1933 (the
     "Securities Act"), the aggregate offering price and the fee have been
     computed upon the basis of the price at which the options may be exercised.
(2)  All of such shares are issuable upon the exercise of outstanding options to
     purchase an aggregate of 715,120 shares at an exercise price of $15.50 per
     share.  Pursuant to Rule 457(h)(1) of the Securities Act, the aggregate
     offering price and the fee have been computed upon the basis of the price
     at which the options may be exercised.
(3)  All of such shares are issuable upon the exercise of outstanding options to
     purchase an aggregate of 2,317,880 shares at an exercise price of $22.50
     per share. Pursuant to Rule 457(h)(1) of the Securities Act, the aggregate
     offering price and the fee have been computed upon the basis of the price
     at which the options may be exercised.
(4)  The price of $29.47 per share, which is the average of the high and low
     price of the Common Stock of the Registrant as reported on the Nasdaq
     National Market on February 23, 1999, is set forth solely for purposes of
     calculating the filing fee pursuant to Rule 457(c) of the Securities Act
     and has been used only for those shares without a fixed exercise price.
(5)  Pursuant to the Rights Agreement of the Registrant, as amended, one right
     to purchase a unit of preferred stock of the Registrant (each a "Preferred
     Stock Purchase Right" or "Right") is deemed to be delivered with each share
     of Common Stock issued by the Registrant.  The Rights currently are not
     separately transferable apart from the Common Stock, nor are they
     exercisable until the occurrence of certain events.  Accordingly, no
     independent value has been attributed to the Rights.

================================================================================
<PAGE>
 
     This Registration Statement registers additional securities of the same
class as other securities for which the Registration Statement No. 33-70114 on
Form S-8 as filed with the Securities and Exchange Commission (the "Commission")
on October 8, 1993 is effective.  Pursuant to General Instruction E of Form S-8,
the contents of the above listed Registration Statement are hereby incorporated
by reference herein.

Item 3.  Incorporation of Documents by Reference
         ---------------------------------------

     In addition to the documents incorporated by reference in Item 3 of
Registration Statement No. 33-70114 on Form S-8, the following document filed
with the Commission is incorporated by reference in this Registration Statement:

     The description of the Registrant's Preferred Stock Purchase Rights which
accompany each share of the Registrant's Common Stock contained in the
Registrant's Registration Statement on Form 8-A/A (Amendment No. 1) filed
pursuant to the Securities Exchange Act of 1934, as amended, on September 30,
1998, including any amendment or report filed for the purpose of updating such
description (File No. 0-21040).
<PAGE>
 
Item 8.  Exhibits.
         -------- 

        Exhibit No.                         Description of Exhibit
        -----------                         ----------------------
                4.1         Amended and Restated Certificate of Incorporation
                            of the Registrant, as amended (filed as Exhibit 3.1
                            to the Registrant's Quarterly Report on Form 10-Q
                            for the quarter ended June 30, 1998, File No.
                            0-21040)*

                4.2         Amended and Restated By-laws of the Registrant
                            (filed as Exhibit 3.2 to the Registrant's
                            Registration Statement on Form S-1, File No.
                            33-56338)*

                4.3         Specimen Stock Certificate representing the Common
                            Stock of the Registrant (filed as Exhibit 4.1 to
                            the Registrant's Registration Statement on Form
                            S-1, File No. 33-56338)*

                4.4         1991 Stock Option Plan of the Registrant (filed as
                            Exhibit 10.2 to the Registrant's Annual Report on
                            Form 10-K for the fiscal year ended December 31,
                            1997, File No. 0-21040)*

                4.5         Rights Agreement, dated as of June 23, 1997, by and
                            between Cambridge Technology Partners
                            (Massachusetts), Inc. and ChaseMellon Shareholder
                            Services, LLC, as Rights Agent (filed as Exhibit
                            4.1 to the Registrant's Registration Statement on
                            Form 8-A/A (Amendment No. 1) filed on September 30,
                            1998, File No. 0-21040)*

                4.6         Amendment No. 1 to the Rights Agreement, dated as
                            of September 30, 1998, by and between Cambridge
                            Technology Partners (Massachusetts), Inc. and
                            ChaseMellon Shareholder Services, LLC, as Rights
                            Agent (filed as Exhibit 4.2 to the Registrant's
                            Registration Statement on Form 8-A/A (Amendment No.
                            1) filed on September 30, 1998, File No. 0-21040)*

                5           Opinion of Testa, Hurwitz & Thibeault, LLP**

               23.1         Consent of Testa, Hurwitz & Thibeault, LLP
                            (included in Exhibit 5)**

               23.2         Consent of PricewaterhouseCoopers LLP**

               24           Power of Attorney (included on signature page
                            hereto)**
-------------
*  Not filed herewith.  In accordance with Rule 411 promulgated pursuant to the
Securities Act of 1933, as amended, reference is made to the documents
previously filed with the Commission, which are incorporated by reference
herein.

**  Filed herewith.
<PAGE>
 
                                  SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, 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 and the Commonwealth of Massachusetts, on
this 25th day of February, 1999.

                                    Cambridge Technology Partners
                                      (Massachusetts), Inc.

                                    By: /s/ Arthur M. Toscanini
                                       ---------------------------
                                       Arthur M. Toscanini
                                       Executive Vice President, Finance

          EACH PERSON WHOSE SIGNATURE appears below this registration statement
hereby constitutes and appoints James K. Sims, Arthur M. Toscanini and James P.
O'Hare, and each of them, with full power to act without the other, his true and
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him and in his name, place and stead in any and all
capacities (until revoked in writing) to sign all amendments (including post-
effective amendments) to this Registration Statement on Form S-8 of Cambridge
Technology Partners (Massachusetts), Inc., and to file the same, with all
exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission or any state securities commission or other
governmental entity pertaining to such registration and sale, granting unto said
attorneys-in-fact and agents, and each of them, full power and authority to do
and perform each and every act and thing requisite and necessary fully to all
intents and purposes as he might or could do in person thereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or their
or his substitute, may lawfully do or cause to be done by virtue hereof.

<TABLE>
<CAPTION>
            Signature                         Capacity                          Date
            ---------                         --------                          ----
<S>                                <C>                                      <C>
 /s/ James K. Sims                 Chief Executive Officer,                 February 25, 1999
---------------------------------  President and Director (Principal
James K. Sims                      Executive Officer)
 
 /s/ Arthur M. Toscanini           Executive Vice President,                February 25, 1999
---------------------------------  Finance, Chief Financial Officer
Arthur M. Toscanini                and Treasurer (Principal
                                   Financial Officer and Principal
                                   Accounting Officer)
 
 /s/ Warren V. Musser              Director                                 February 25, 1999
---------------------------------
Warren V. Musser 

 /s/ Robert E. Keith, Jr.          Director                                 February 25, 1999
---------------------------------
Robert E. Keith, Jr. 

 /s/ Jack L. Messman               Director                                 February 25, 1999
---------------------------------
Jack L. Messman 

 /s/ John W. Poduska, Sr.          Director                                 February 25, 1999
---------------------------------
John W. Poduska, Sr.  

 /s/ James I. Cash, Jr.            Director                                 February 25, 1999
---------------------------------
James I. Cash, Jr.  

 /s/ James D. Robinson III         Director                                 February 25, 1999
---------------------------------
James D. Robinson III 
</TABLE>
<PAGE>
 
                                 EXHIBIT INDEX

    Exhibit No.                            Description of Exhibit
    -----------                            ----------------------
            4.1              Amended and Restated Certificate of Incorporation
                             of the Registrant, as amended (filed as Exhibit 3.1
                             to the Registrant's Quarterly Report on Form 10-Q
                             for the quarter ended June 30, 1998, File No.
                             0-21040)*

            4.2              Amended and Restated By-laws of the Registrant
                             (filed as Exhibit 3.2 to the Registrant's
                             Registration Statement on Form S-1, File No.
                             33-56338)*

            4.3              Specimen Stock Certificate representing the Common
                             Stock of the Registrant (filed as Exhibit 4.1 to
                             the Registrant's Registration Statement on Form
                             S-1, File No. 33-56338)*

            4.4              1991 Stock Option Plan of the Registrant (filed as
                             Exhibit 10.2 to the Registrant's Annual Report on
                             Form 10-K for the fiscal year ended December 31,
                             1997, File No. 0-21040)*

            4.5              Rights Agreement, dated as of June 23, 1997, by and
                             between Cambridge Technology Partners
                             (Massachusetts), Inc. and ChaseMellon Shareholder
                             Services, LLC, as Rights Agent (filed as Exhibit
                             4.1 to the Registrant's Registration Statement on
                             Form 8-A/A (Amendment No. 1) filed on September 30,
                             1998, File No. 0-21040)*

            4.6              Amendment No. 1 to the Rights Agreement, dated as
                             of September 30, 1998, by and between Cambridge
                             Technology Partners (Massachusetts), Inc. and
                             ChaseMellon Shareholder Services, LLC, as Rights
                             Agent (filed as Exhibit 4.2 to the Registrant's
                             Registration Statement on Form 8-A/A (Amendment No.
                             1) filed on September 30, 1998, File No. 0-21040)*

            5                Opinion of Testa, Hurwitz & Thibeault, LLP**

           23.1              Consent of Testa, Hurwitz & Thibeault, LLP
                             (included in Exhibit 5)**

           23.2              Consent of PricewaterhouseCoopers LLP**

           24                Power of Attorney (included on signature page
                             hereto)**

-------------
*  Not filed herewith. In accordance with Rule 411 promulgated pursuant to the
Securities Act of 1933, as amended, reference is made to the documents
previously filed with the Commission, which are incorporated by reference
herein.

**  Filed herewith.