We report a case of malignant melanotic melanoma involving the extrahepatic biliary tract in a 34-year-old white woman. The diagnosis was established using conventional light microscopic examination and immunohistochemical stains. The clinical absence of any primary cutaneous or visceral melanoma suggests that the tumor arose primarily from the biliary tract. To our knowledge, only two previous cases of malignant melanoma of the common bile duct have been reported in the literature.