A case of malignant fibrous histiocytoma that developed at the site of an infected metallic implant is presented. The total hip endoprosthesis was composed of a cobalt-chromium alloy. There was a relatively short latency period (less than 2 years) between the initial surgery and the development of malignancy in this patient. The authors urge development of a tumor registry to discover if the association between hip replacement and malignancy is coincidental.