Anadarko Begins Western Gas Partners, LP Initial Public Offering

Anadarko Petroleum Corporation announced that Western Gas Partners, LP ("Western Gas Partners") has commenced its initial public offering of 18,750,000 common units representing limited partner interests, pursuant to a registration statement on Form S-1 previously filed with the U.S. Securities and Exchange Commission (the "SEC"). The underwriters will be granted a 30-day option to purchase up to an additional 2,812,500 common units. The common units will be listed on the New York Stock Exchange and traded under the symbol "WES."

Upon conclusion of the offering, the public will own an approximate 35% limited partner interest in Western Gas Partners, or an approximate 40% limited partner interest if the underwriters exercise in full their option to purchase additional common units. Anadarko will own the remaining equity interests in Western Gas Partners, including the general partner interest.

UBS Investment Bank, Citi, Credit Suisse and Morgan Stanley will act as joint book-running managers of the offering. Banc of America Securities LLC, Goldman, Sachs & Co., JPMorgan, Lehman Brothers and Wachovia Securities will act as senior co-managers, and Scotia Capital, Bear, Stearns & Co. Inc., Friedman Billings Ramsey and Stifel Nicolaus will act as co-managers, for the offering.

This offering of common units will be made only by means of a prospectus. A written prospectus satisfying the requirements of Section 10 of the Securities Act of 1933, when available, may be obtained from the offices of: (i) UBS Securities LLC, Prospectus Department, 299 Park Avenue, New York, New York 10171, phone: 888-827-7275 or 212-713-2626; (ii) Citigroup Global Markets Inc., Brooklyn Army Terminal, Attn: Prospectus Delivery Department, 140 58th Street, Brooklyn, New York 11220, phone: 800-831-9146; (iii) Credit Suisse Securities (USA) LLC, Attn: Prospectus Department, One Madison Avenue, New York, New York 10010, phone: 800-221-1037; or (iv) Morgan Stanley & Co. Incorporated, Attn: Prospectus Department, 180 Varick Street, 2nd Floor, New York, New York 10014, e-mail: