A series of forty patients who had forty femoral shaft fractures that were treated with static interlocking nailing were analyzed to determine the incidence of union of the fracture without planed conversion from static to dynamic intramedullary fixation as a technique to stimulate healing of the fracture. All of the forty cases were nailed using closed method under the guide of a image intensifier. The time to full weight was individualized for each patient and depend on the degree of comminution, the postoperative cortical contact between the major fragments, the presence of bridging callus as seen on follow up x-rays, and the patients mobility according to the associated injuries. Healing occurred in thirty nine(97%) of the forty fractures of the femoral shaft that had been treated with static interlocking nailing without dynamizaton. Only one patient needed conversion from static to dynamic interlocking fixation to promote fracture healing. This patient had a delayed union after closed interlocking nailing of Gustilo type I open midshaft fracture associated with Winquist type II comminution. We concluded that static interlocking nailing for femoral shaft fractures does not seem to inhibit the fracture healing process, and that conversion to dynamic intramedullary fixation is needed only for exceptional cases of delayed union.