Gluteal fibrosis is rare in Kores. We thought the probable primary etiology of gluteal fibrosis might be repeated intramuscular injection into the buttock, Inability to adduct the legs in the sitting position and flex the hips in neutral position had been observed. Four cases(3 persons) of gluteal fibrosis in adult from October 1986 to February 1987 are presented with much improvement of squatting and flexion of hip in neutral position after operation.