Curtis, Mallet-Prevost, Colt & Mosle llp

                        Attorneys and Counsellors at Law
Frankfurt    Muscat            101 Park Avenue           Telephone 212-696-6000
Houston      Paris       New York, New York 10178-0061   Facsimile 212-697-1559
London       Stamford                                    Voice Mail 212-696-6028
Mexico City  Washington,                                 E-Mail info@cm-p.com
D.C.                                                     Internet www.cm-p.com
Milan


                                                 November 14, 2005

Century Aluminum Company
2511 Garden Road
Building A, Suite 200
Monterey, California  93940


Ladies and Gentlemen:

     We have acted as special counsel for Century Aluminum Company, a Delaware
corporation (the "Company"), with respect to the proposed registration and sale
by the Company of an additional 3,000,000 shares of the Company's common stock
("Common Stock") issuable upon the exercise of options granted or to be granted
under the Company's Amended and Restated 1996 Stock Incentive Plan (the "Plan"),
covered by a Registration Statement on Form S-8 (the "Registration Statement")
filed with the Securities and Exchange Commission under the Securities Act of
1933, as amended.

     In connection herewith, we have examined the Restated Certificate of
Incorporation and the Amended and Restated Bylaws of the Company, the
Registration Statement and all exhibits thereto, and such other documents as we
have considered necessary.

     Based upon such examination, it is our opinion that the shares of Common
Stock proposed to be sold by the Company, when sold pursuant to the Plan and the
resolutions of the Board of Directors of the Company (and the Compensation
Committee thereof) authorizing the same, will be validly issued, fully paid and
nonassessable. In rendering this opinion, we have assumed that the exercise
price of the options will not be less than the par value of the shares subject
thereto.

     This opinion is limited to questions arising under the laws of the General
Corporation Law of the State of Delaware, including applicable provisions of the
Delaware Constitution and the reported judicial decisions interpreting those
laws, and we express no opinion as to the laws of any other jurisdiction.




Curtis, Mallet-Prevost, Colt & Mosle LLP
   Attorneys and Counsellors at Law         Page 2  November 14, 2005



     We hereby consent to the use of the foregoing opinion as an exhibit to the
Registration Statement.



                                                    Very truly yours,

                                    /s/ Curtis, Mallet-Prevost, Colt & Mosle LLP