This study of wedge osteotomy in the treatment of marked slipping of the capital femoral epiphysis, with a follow-up of from one and a half to twelve years (average, 5.8 years), evaluates index of hip function, roentgenographic changes, gait, and history of pain. Good results are dependent upon good exposure, extreme care in preservation of the blood supply to the femoral head, adequate wedge resection of the femoral neck, effecting a valgus position of the epiphysis at surgery, proper placement of the plane of osteotomy, and adequate internal fixation supplemented by external fixation when necessary.