Four patients were treated who had limited flexion of the hips and various degrees of contracture of the abduction and external rotator muscles because of fibrosis of the gluteus maximus muscle. Each patient had a typical restriction of motion such that an affected hip could not be flexed in the usual sagittal plane, but had to be flexed in abduction. Genetic, congenital and postnatal factors have been suggested as the cause of fibrosis of gluteus maximus muscle. Three of the 4 patients reported here are of congenital origin and another one is of postnatal factor repeated intramuscular injections. Excellent correction of the hip contracture was achieved in all patients by division of the fibrotic bands.