The clinical, radiographic, and pathologic findings of 2 cases of malignant fibrous histiocytoma (MFH) of the renal capsule are reported and the 17 previous cases in the literature reviewed. Preoperative differentiation from renal adenocarcinoma was precluded by the overlap in clinical, laboratory, and radiologic findings, although MFH usually presented with a normal urine analysis and less parenchymal involvement on imaging studies. Pathologic differential diagnosis and therapeutic approaches are presented.