Legg-Calve-Perthes disease is a hip disorder of undetermined etiology, occurring in children and characterized by necrosis and repair of the proximal femoral epiphysis. Many methods of the treatment were reported with good result and the goals of them were prevention of deformity of femoral head and secondary osteoarthritis of femoral head with concept of containment. The purpose of this study is to determine the significance of soft tissue release operation in patient of Legg-Calve-Perthes disease, whose prognosis will be poor by clinical and rsdiological evaluation at diagnosis. Soft tissue release operation was carried out 21 hips of 19 patients of Legg-Calve-Perthes disease at Severance Hospital from January 1986 to October 1987 and satisfactory result was obtained. We consider our method as new, effective treatment modality and its significance is to reduce abnormal pressure to femoral head, to restore normal range of motion, to avoid recurrent ischemia, and, finally, to avoid progression of deformity by soft tissue release operation.