<PAGE>


                                            Registration No. 333-
================================================================================


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                              ---------------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                              --------------------

                                LIGHTBRIDGE, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)


DELAWARE                                                              04-3065140
(STATE OR OTHER JURISDICTION OF                                 (I.R.S. EMPLOYER
INCORPORATION OR ORGANIZATION)                               IDENTIFICATION NO.)


67 SOUTH BEDFORD STREET                                                    01803
BURLINGTON, MA                                                        (ZIP CODE)
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)


               LIGHTBRIDGE, INC. 1996 EMPLOYEE STOCK PURCHASE PLAN
                            (FULL TITLE OF THE PLAN)
                              --------------------

                             MS. PAMELA D. A. REEVE
                      President and Chief Executive Officer
                                LIGHTBRIDGE, INC.
                             67 South Bedford Street
                         Burlington, Massachusetts 01803
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (781) 359-4000
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)
                              --------------------

                                 WITH COPIES TO:
                         John D. Patterson, Jr., Esquire
                             Foley, Hoag & Eliot LLP
                             One Post Office Square
                           Boston, Massachusetts 02109
                                 (617) 832-1000
                              --------------------

                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
====================================================================================================================
       TITLE OF                                         PROPOSED               PROPOSED
      SECURITIES                  AMOUNT                 MAXIMUM                MAXIMUM              AMOUNT OF
         TO BE                     TO BE             OFFERING PRICE            AGGREGATE           REGISTRATION
      REGISTERED                REGISTERED              PER SHARE           OFFERING PRICE              FEE
-------------------------- --------------------- ----------------------- --------------------- ---------------------
-------------------------- --------------------- ----------------------- --------------------- ---------------------
<S>                        <C>                   <C>                     <C>                   <C>
      Common Stock,
     $.01 par value            100,000 (1)            $22.6875 (2)            $2,268,750              $598.95
-------------------------- --------------------- ----------------------- --------------------- ---------------------
</TABLE>


         (1) Represents shares of Common Stock issuable upon exercise of stock
options granted pursuant to the Lightbridge 1996 Employee Stock PurchasePlan
(the "1996 Purchase Plan").
         (2) Calculated pursuant to Rule 457(c) and (h)(1) under the Securities
Act of 1933 based on the average of the high and low sales price of the common
stock as reported on the Nasdaq National Market on August 4, 2000.




================================================================================


<PAGE>

         This Registration Statement covers 100,000 shares of our common stock
issuable pursuant to our 1996 Employee Stock Purchase Plan. These shares are in
addition to the 100,000 shares of common stock registered pursuant to the
Registration Statement on Form S-8, File No. 333-21585, which we filed with the
Securities and Exchange Commission on February 11, 1997.

         The contents of our Registration Statement on Form S-8, File No.
333-21585, is incorporated herein by reference.


<PAGE>

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 8.  EXHIBITS.

<TABLE>
<CAPTION>

         EXHIBIT NO.                DESCRIPTION
         <S>                        <C>

         4.1 (1)                    Amended and Restated Certificate of Incorporation of the Company
         4.2 (1)                    Amended and Restated By-Laws of the Company
         4.3 (2)                    Amendment to Amended and Restated  By-Laws of the Company, adopted
                                    October 29, 1998
         4.4 (1)                    Specimen Certificate for Common Stock of the Company
         4.5 (3)                    Rights Agreement dated as of November 14, 1997, between Lightbridge,
                                    Inc. and American Stock Transfer and Trust Company, as Rights Agent
         4.6 (3)                    Form of Certificate of Designation of Series A Participating Cumulative
                                    Preferred Stock of Lightbridge, Inc.
         4.7 (3)                    Form of Right Certificate
         4.8                        1996 Employee Stock Purchase Plan, as amended
         5.1                        Opinion of Foley, Hoag & Eliot LLP
         23.1                       Independent Auditors' Consent of Deloitte & Touche LLP
         23.2                       Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1)
         24.1                       Power of Attorney (contained on the signature page)

-------------------------------------
</TABLE>


(1)      Incorporated by reference from the Company's Registration Statement on
         Form S-1, as amended (File No. 333-6589)
(2)      Incorporated by reference from the Company's Quarterly Report on Form
         10-Q for the quarter ended September 30, 1998.
(3)      Incorporated by reference from the Company's Registration Statement on
         Form 8-A, as filed with the Securities and Exchange Commission on
         November 21, 1997.




<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 Town of Burlington, Massachusetts, on this
11th day of August, 2000.

                                       LIGHTBRIDGE, INC.


                                        By: /s/ Pamela D.A. Reeve
                                            -------------------------------
                                            Pamela D.A. Reeve
                                            President & Chief Executive Officer

                                POWER OF ATTORNEY

         KNOW ALL MEN BY THESE PRESENTS that each individual whose signature
appears below constitutes and appoints Pamela D.A. Reeve as the undersigned's
true and lawful attorney-in-fact and agent with full power of substitution, for
the undersigned and in the undersigned's name, place and stead, in any and all
capacities, to sign any and all amendments (including post-effective amendments)
to this Registration Statement, and to file the same, with all exhibits thereto,
and all documents in connection therewith, with the Commission, granting unto
said attorney-in-fact and agent full power and authority to do and perform each
and every act and thing which she may deem necessary or advisable to be done in
connection with this Registration Statement, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or any
substitute or substitutes for her may lawfully do or cause to be done by virtue
hereof.

         Pursuant to the requirements of the Securities Act, this registration
statement has been signed by the following persons in the indicated capacities
as of August 11th, 2000.

<TABLE>
<CAPTION>

              SIGNATURE                    TITLE                                 DATE
<S>                                 <C>                                         <C>
                                    President, Chief Executive Officer,
/s/ Pamela D. A. Reeve              and Director (Principal                      August 11, 2000
----------------------------        Executive Officer)
    Pamela D. A. Reeve


/s/ Torrence C. Harder              Director                                     August 11, 2000
----------------------------
    Torrence C. Harder


/s/ D. Quinn Mills                  Director                                     August 11, 2000
----------------------------
    D. Quinn Mills


/s/ Debora J. Wilson                Director                                     August 11, 2000
----------------------------
    Debora J. Wilson


/s/ Andrew Mills                    Director                                     August 11, 2000
----------------------------
    Andrew Mills
</TABLE>
[{"type": "S-8", "sequence": "1", "filename": "s-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 9540}]
{"company-data": {"conformed-name": "LIGHTBRIDGE INC", "cik": "0001017172", "assigned-sic": "4812", "irs-number": "043065140", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-43586", "film-number": "694463"}, "business-address": {"street1": "67 S BEDFORD ST", "city": "BURLINGTON", "state": "MA", "zip": "01803", "phone": "6173594000"}, "mail-address": {"street1": "67 SOUTH BEDFORD STREET", "city": "BURLINGTON", "state": "MA", "zip": "01803"}}
Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                              ---------------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                              --------------------

                                LIGHTBRIDGE, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

DELAWARE                                                              04-3065140
(STATE OR OTHER JURISDICTION OF                                 (I.R.S. EMPLOYER
INCORPORATION OR ORGANIZATION)                               IDENTIFICATION NO.)

67 SOUTH BEDFORD STREET                                                    01803
BURLINGTON, MA                                                        (ZIP CODE)
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)

               LIGHTBRIDGE, INC. 1996 EMPLOYEE STOCK PURCHASE PLAN
                            (FULL TITLE OF THE PLAN)
                              --------------------

                             MS. PAMELA D. A. REEVE
                      President and Chief Executive Officer
                                LIGHTBRIDGE, INC.
                             67 South Bedford Street
                         Burlington, Massachusetts 01803
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (781) 359-4000
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)
                              --------------------

                                 WITH COPIES TO:
                         John D. Patterson, Jr., Esquire
                             Foley, Hoag & Eliot LLP
                             One Post Office Square
                           Boston, Massachusetts 02109
                                 (617) 832-1000
                              --------------------

                         CALCULATION OF REGISTRATION FEE
====================================================================================================================
       TITLE OF                                         PROPOSED               PROPOSED
      SECURITIES                  AMOUNT                 MAXIMUM                MAXIMUM              AMOUNT OF
         TO BE                     TO BE             OFFERING PRICE            AGGREGATE           REGISTRATION
      REGISTERED                REGISTERED              PER SHARE           OFFERING PRICE              FEE
-------------------------- --------------------- ----------------------- --------------------- ---------------------
-------------------------- --------------------- ----------------------- --------------------- ---------------------
Common Stock,
     $.01 par value            100,000 (1)            $22.6875 (2)            $2,268,750              $598.95
-------------------------- --------------------- ----------------------- --------------------- ---------------------
(1) Represents shares of Common Stock issuable upon exercise of stock
options granted pursuant to the Lightbridge 1996 Employee Stock PurchasePlan
(the "1996 Purchase Plan").
         (2) Calculated pursuant to Rule 457(c) and (h)(1) under the Securities
Act of 1933 based on the average of the high and low sales price of the common
stock as reported on the Nasdaq National Market on August 4, 2000.

================================================================================
This Registration Statement covers 100,000 shares of our common stock
issuable pursuant to our 1996 Employee Stock Purchase Plan. These shares are in
addition to the 100,000 shares of common stock registered pursuant to the
Registration Statement on Form S-8, File No. 333-21585, which we filed with the
Securities and Exchange Commission on February 11, 1997.

         The contents of our Registration Statement on Form S-8, File No.
333-21585, is incorporated herein by reference.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 8.  EXHIBITS.
EXHIBIT NO.                DESCRIPTION
4.1 (1)                    Amended and Restated Certificate of Incorporation of the Company
         4.2 (1)                    Amended and Restated By-Laws of the Company
         4.3 (2)                    Amendment to Amended and Restated  By-Laws of the Company, adopted
                                    October 29, 1998
         4.4 (1)                    Specimen Certificate for Common Stock of the Company
         4.5 (3)                    Rights Agreement dated as of November 14, 1997, between Lightbridge,
                                    Inc. and American Stock Transfer and Trust Company, as Rights Agent
         4.6 (3)                    Form of Certificate of Designation of Series A Participating Cumulative
                                    Preferred Stock of Lightbridge, Inc.
         4.7 (3)                    Form of Right Certificate
         4.8                        1996 Employee Stock Purchase Plan, as amended
         5.1                        Opinion of Foley, Hoag & Eliot LLP
         23.1                       Independent Auditors' Consent of Deloitte & Touche LLP
         23.2                       Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1)
         24.1                       Power of Attorney (contained on the signature page)

-------------------------------------
(1)      Incorporated by reference from the Company's Registration Statement on
         Form S-1, as amended (File No. 333-6589)
(2)      Incorporated by reference from the Company's Quarterly Report on Form
         10-Q for the quarter ended September 30, 1998.
(3)      Incorporated by reference from the Company's Registration Statement on
         Form 8-A, as filed with the Securities and Exchange Commission on
         November 21, 1997.
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 Town of Burlington, Massachusetts, on this
11th day of August, 2000.

                                       LIGHTBRIDGE, INC.

                                        By: /s/ Pamela D.A. Reeve
                                            -------------------------------
                                            Pamela D.A. Reeve
                                            President & Chief Executive Officer

                                POWER OF ATTORNEY

         KNOW ALL MEN BY THESE PRESENTS that each individual whose signature
appears below constitutes and appoints Pamela D.A. Reeve as the undersigned's
true and lawful attorney-in-fact and agent with full power of substitution, for
the undersigned and in the undersigned's name, place and stead, in any and all
capacities, to sign any and all amendments (including post-effective amendments)
to this Registration Statement, and to file the same, with all exhibits thereto,
and all documents in connection therewith, with the Commission, granting unto
said attorney-in-fact and agent full power and authority to do and perform each
and every act and thing which she may deem necessary or advisable to be done in
connection with this Registration Statement, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any of them, or any
substitute or substitutes for her may lawfully do or cause to be done by virtue
hereof.

         Pursuant to the requirements of the Securities Act, this registration
statement has been signed by the following persons in the indicated capacities
as of August 11th, 2000.
SIGNATURE                    TITLE                                 DATE
President, Chief Executive Officer,
/s/ Pamela D. A. Reeve              and Director (Principal                      August 11, 2000
----------------------------        Executive Officer)
    Pamela D. A. Reeve

/s/ Torrence C. Harder              Director                                     August 11, 2000
----------------------------
    Torrence C. Harder

/s/ D. Quinn Mills                  Director                                     August 11, 2000
----------------------------
    D. Quinn Mills

/s/ Debora J. Wilson                Director                                     August 11, 2000
----------------------------
    Debora J. Wilson

/s/ Andrew Mills                    Director                                     August 11, 2000
----------------------------
    Andrew Mills