Failure to determine distal femoral screw hole position can sometimes prolong operating time for placing interlocking screw and increased radiation hazard. We attempted to assess progress in the insertion of distal locking screw with target device. Insertion method of distal locking screw in femoral nail that uses target device improved the accuracy of distal screw placement and reduced the radiation exposure. The authors analyzed 30 patients(33 cases) of the femur shaft fractures that treated by interlocking IM nailing using target divice in the Department of Orthpaedic Surgery, Chung-Ang university from August 1990 to July 1994. Among these patients, except 6 cases, all of the distal femoral drill holes attempted were successfully made with the first pass of a dirll without image intensiner monitoring.