Generally, pathologic fracture with solitary bone cyst was treated by plaster immobilization to stabilize the fracture site and there-after local steroid injection and curettage and bone graft in the remaining cyst. However, pathologic fracture involving weight bearing bone such as trochanter of the femur showed many complications : coxa, vara, avascular necrosis of femoral head, osteochondritis dissecans if they are treated by conservative method. We treated operatively for two unstable pathologic fractures of the trochanteric region of femur with large solitary bone cyst by primary curettage and autogenous bone graft with internal fixation and obtained satisfactory results.