Closed intramehl4uy nailing has become increasingly popular in the management of fractures of the femur because of a high rate of union, a low rate of infection. and excellent return of function. But it requires good availavillity of equipment and surgeon's skill and experience. latrogenic femur neck fracture can occur as a complication of closed intramedullary nailing of femur shaft fracture. The authors report five cases of this complication and analyze these five cases in the viewpoint of causal technical errors and suggest some technical points to avoid this complication.