Clinical and radiological studies were performed on avascular necrosis of the femoral head (ANF) in 220 hips 140 patients including 51 hips of 28 patients with systemic lupus erythe-matosus (SLE group). Sixty-nine hips of 41 patients wee treated with corticosteroid adminis-tration (S group) and 100 hips of 71 patients without corticosteroid administration (Non-S group). All patients with SLE were treated with corticosteroid adminstration. Thirty-one femoral heads (11 heads of SLE group, 9 heads of S group and 11 heads of Non-S group) were resected at operations nad studied histologically. Seventy-seven hips at an early stage showed that collapse of the femoral heads occurred in 80% without 3 years and no differences were found among these group. In the SLE group, bilateral involvement, multiple bone necrosis and predilection for young females were apparent. Collapse of the femoral head and subcapital fractures were more frequently seen in the SLE group. Histologically, almost all heads even in the SLE group showed repair process such as enchondral ossification and appositional bone formation, while the heads with subcapital fracture showed no such no such changes.