Piriformis fossa is chosen for the entry point of the intramedullary nail insertion for the broken femoral shaft. To evaluate the correct entry point selection, the use of the usual operation table and short skin incision, we tried the percutaneous interlocking intramedullary nailing with retrograde guide wire insertion technique. The guide wire is inserted through the short skin incision on the anterior thigh and comes out through piriformis fossa easily. Through over the guide wire the femoral nail was inserted with only short skin incision. And the trick makes no difference except the convenience compared with the antegrade guide wire insertion technique. It is considered as a useful tip of the intramedullary nailing of the femoral shaft fracture.