EXHIBIT 21 LIST OF SIGNIFICANT SUBSIDIARIES Anadarko E&P Company, LP a Delaware limited partnership, Anadarko Holding Company a Utah corporation, Anadarko Canada Energy Ltd. an Alberta, Canada corporation, Anadarko Canada Corporation an Alberta, Canada corporation, Anadarko Land Corp. a Nebraska corporation, Anadarko Algeria Company, LLC a Delaware limited liability company, Anadarko Energy Services Company a Delaware corporation, APC Venezuela, S.R.L. a Venezuela limited liability company, Bitter Creek Coal Company a Utah corporation