<PAGE>   1
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 28, 2000

                                                  REGISTRATION NO. 333-

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


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



                            CENTURY ALUMINUM COMPANY
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

                DELAWARE                                 13-3070826
    (State or other jurisdiction of         (I.R.S. Employer Identification No.)
     Incorporation or organization)

            2511 GARDEN ROAD                               01238
         BUILDING A, SUITE 200                           (Zip code)
          MONTEREY, CALIFORNIA
(Address of principal executive offices)


                            CENTURY ALUMINUM COMPANY
                            1996 STOCK INCENTIVE PLAN
                            (FULL TITLE OF THE PLAN)


                                GERALD A. MEYERS
                                    PRESIDENT
                            CENTURY ALUMINUM COMPANY
                                2511 GARDEN ROAD
                              BUILDING A, SUITE 200
                           MONTEREY, CALIFORNIA 01238
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (831) 642-9300
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)



                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                   Proposed                Proposed
                                                                   Maximum                 Maximum
    Title of Securities to be           Amount to be            Offering Price            Aggregate               Amount of
           Registered                    Registered              Per Share(1)         Offering Price (1)       Registration Fee
-------------------------------------------------------------------------------------------------------------------------------
<S>                                    <C>                      <C>                   <C>                      <C>
Common Stock, $.01 par value .....     300,000 Shares              $12.875              $3,862,500.00             $1,019.70
</TABLE>

(1) Estimated solely for the purpose of computing the registration fee pursuant
    to Rule 457, based on the average of the high and low prices for the Common
    Stock as reported on the Nasdaq National Market System on July 25, 2000.
<PAGE>   2
                           INCORPORATION BY REFERENCE

         This Registration Statement on Form S-8 relates to the registration of
additional shares reserved for issuance under the registrant's 1996 Stock
Incentive Plan. Pursuant to General Instruction E of Form S-8, the contents of
the Registration Statement on Form S-8 (Registration No. 333-15689) filed with
the Securities and Exchange Commission and effective on November 6, 1996 is
hereby incorporated by reference herein.




                                      -2-
<PAGE>   3
                                   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 Monterey, State of California, on the 28th day of
July, 2000.


                                    Century Aluminum Company

                                    By: /s/ Craig A. Davis
                                        ----------------------------------------
                                    Name:   Craig A. Davis
                                    Title:  Chairman and Chief Executive Officer


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



<TABLE>
<CAPTION>
               SIGNATURE                                 TITLE                                  DATE
               ---------                                 -----                                  ----
<S>                                        <C>                                              <C>
     /s/ Craig A. Davis                        Chairman, Chief Executive                    July 28, 2000
------------------------------------             Officer and Director
         Craig A. Davis

     /s/ Gerald A. Meyers                     President, Chief Operating                    July 28, 2000
------------------------------------             Officer and Director
         Gerald A. Meyers

     /s/ David W. Beckley                    Executive Vice President and                   July 28, 2000
------------------------------------            Chief Financial Officer
         David W. Beckley                  (Principal Financial Officer and
                                             Principal Accounting Officer)

     /s/ Roman A. Bninski                              Director                             July 28, 2000
------------------------------------
         Roman A. Bninski

     /s/ John C. Fontaine                              Director                             July 28, 2000
------------------------------------
         John C. Fontaine

     /s/ John P. O'Brien                               Director                             July 28, 2000
------------------------------------
         John P. O'Brien

     /s/ Stuart M. Schreiber                           Director                             July 28, 2000
------------------------------------
         Stuart M. Schreiber

     /s/ Willy R. Strothotte                           Director                             July 28, 2000
------------------------------------
         Willy R. Strothotte
</TABLE>




                                      -3-
<PAGE>   4
                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>
     Exhibit No.                                Description of Exhibit
     -----------                                ----------------------
<S>                        <C>
         5                 Opinion of Curtis, Mallet-Prevost, Colt & Mosle LLP

         23.1              Consent of Deloitte & Touche LLP

         23.2              Consent of Curtis, Mallet-Prevost, Colt & Mosle LLP (included in Exhibit 5)
</TABLE>




                                      -4-
[{"type": "S-8", "sequence": "1", "filename": "s-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 6863}]
{"company-data": {"conformed-name": "CENTURY ALUMINUM CO", "cik": "0000949157", "assigned-sic": "3350", "irs-number": "133070826", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-42534", "film-number": "681567"}, "business-address": {"street1": "2511 GARDEN ROAD", "street2": "BUILDING A SUITE 200", "city": "MONTEREY", "state": "CA", "zip": "93940", "phone": "3042736000"}, "mail-address": {"street1": "2511 GARDEN ROAD", "street2": "BUILDING A SUITE 200", "city": "MONTEREY", "state": "CA", "zip": "93940"}}
1
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 28, 2000

                                                  REGISTRATION NO. 333-

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                            CENTURY ALUMINUM COMPANY
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

                DELAWARE                                 13-3070826
    (State or other jurisdiction of         (I.R.S. Employer Identification No.)
     Incorporation or organization)

            2511 GARDEN ROAD                               01238
         BUILDING A, SUITE 200                           (Zip code)
          MONTEREY, CALIFORNIA
(Address of principal executive offices)

                            CENTURY ALUMINUM COMPANY
                            1996 STOCK INCENTIVE PLAN
                            (FULL TITLE OF THE PLAN)

                                GERALD A. MEYERS
                                    PRESIDENT
                            CENTURY ALUMINUM COMPANY
                                2511 GARDEN ROAD
                              BUILDING A, SUITE 200
                           MONTEREY, CALIFORNIA 01238
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (831) 642-9300
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)

                         CALCULATION OF REGISTRATION FEE
Proposed                Proposed
                                                                   Maximum                 Maximum
    Title of Securities to be           Amount to be            Offering Price            Aggregate               Amount of
           Registered                    Registered              Per Share(1)         Offering Price (1)       Registration Fee
-------------------------------------------------------------------------------------------------------------------------------
Common Stock, $.01 par value .....     300,000 Shares              $12.875              $3,862,500.00             $1,019.70
(1) Estimated solely for the purpose of computing the registration fee pursuant
    to Rule 457, based on the average of the high and low prices for the Common
    Stock as reported on the Nasdaq National Market System on July 25, 2000.
2
                           INCORPORATION BY REFERENCE

         This Registration Statement on Form S-8 relates to the registration of
additional shares reserved for issuance under the registrant's 1996 Stock
Incentive Plan. Pursuant to General Instruction E of Form S-8, the contents of
the Registration Statement on Form S-8 (Registration No. 333-15689) filed with
the Securities and Exchange Commission and effective on November 6, 1996 is
hereby incorporated by reference herein.

                                      -2-
3
                                   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 Monterey, State of California, on the 28th day of
July, 2000.

                                    Century Aluminum Company

                                    By: /s/ Craig A. Davis
                                        ----------------------------------------
                                    Name:   Craig A. Davis
                                    Title:  Chairman and Chief Executive Officer

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
SIGNATURE                                 TITLE                                  DATE
               ---------                                 -----                                  ----
/s/ Craig A. Davis                        Chairman, Chief Executive                    July 28, 2000
------------------------------------             Officer and Director
         Craig A. Davis

     /s/ Gerald A. Meyers                     President, Chief Operating                    July 28, 2000
------------------------------------             Officer and Director
         Gerald A. Meyers

     /s/ David W. Beckley                    Executive Vice President and                   July 28, 2000
------------------------------------            Chief Financial Officer
         David W. Beckley                  (Principal Financial Officer and
                                             Principal Accounting Officer)

     /s/ Roman A. Bninski                              Director                             July 28, 2000
------------------------------------
         Roman A. Bninski

     /s/ John C. Fontaine                              Director                             July 28, 2000
------------------------------------
         John C. Fontaine

     /s/ John P. O'Brien                               Director                             July 28, 2000
------------------------------------
         John P. O'Brien

     /s/ Stuart M. Schreiber                           Director                             July 28, 2000
------------------------------------
         Stuart M. Schreiber

     /s/ Willy R. Strothotte                           Director                             July 28, 2000
------------------------------------
         Willy R. Strothotte
-3-
4
                                INDEX TO EXHIBITS
Exhibit No.                                Description of Exhibit
     -----------                                ----------------------
5                 Opinion of Curtis, Mallet-Prevost, Colt & Mosle LLP

         23.1              Consent of Deloitte & Touche LLP

         23.2              Consent of Curtis, Mallet-Prevost, Colt & Mosle LLP (included in Exhibit 5)
-4-