Fracture of the femur during total hip arthroplasty presents the simultaneous problems of prosthetic stability and fracture treatment. The treatment of such fractures can be complex and is one of the major challenges and this complication is associated with a high morbidity and a significant delay in convalescence. Among the 237 cases, who were treated by cementless total hip arthroplasty from Jan. 1986 to Dec. 1992, 13 cases of femoral fracture were experienced. They usually occured during insertion of prosthesis and preparation of the medullary canal. There were 6 cases of type II fracture, 1 case of type III fracture, 5 cases of type IV fracture and 1 case of type V fracture according to AAOS classification. All of the fracture healed, but the prognosis of these cases must be determined by follow up. We recommend that femoral fractures can be prevented by accurate preoperative evaluation of the size of the femoral canal, identification and management of the predisposing factors for intraoperative fractures.