From January 1, 1971, to January 1, 1976, 173 renal allografts were transplanted into 146 patients. Intravenous methylprednisolone (IVMP) was given to all mismatched recipients in a dose of 1 Gm. on the day of transplant and in varying amounts during acute allograft rejection. In 7 patients, 4.8 per cent of 146 patients and 4 per cent of 173 allografts, with a minimum follow-up of fifteen months avascular necrosis of one or more joints developed with an average of 9.4 months after transplantation and a range of five to eighteen months. The total dose of IVMP given to the patients with aseptic necrosis varied between 3 and 18 Gm. from the time of transplantation until the onset of skeletal symptoms. This incidence was nearly identical to the 5 per cent of 242 patients and 4.3 per cent of 276 renal allografts from the same center performed between January 1, 1963, and January 1, 1971, when intravenous steroid pulse therapy was not utilized. Since January, 1971, total joint replacement of the hip or knee were performed in 4 of the 7 affected patients six to sixteen months after the onset of symptoms. Renal function remained stable after surgery in all 4 patients. Virtually normal range of motion was present within three months after surgery. Although the controversy of steroid therapy in the pathogenesis of avascular necrosis still exists, judicious use of high-dose IVMP therapy does not appear to increase its incidence. Early surgery is recommended when the radiologic evidence confirms the clinical findings of avascular necrosis in order to ameliorate pain, correct restriction of movement, and promote full rehabilitation.