Despite advances in fracture management. the long bone fracture have high rate of morbidity. Recently interlocking intramedullary nailing have gained increasing attention and acceptance as a treatment modality for femoral shaft fracture. Early proper fixation of long bone fractures is needed for early mobiliaation of the patient to facilitate pulmonary care and to prevent secondary complications due to prolonged bed rest and traction We treated twenty-eight patients of femur shaft fracture using interlocking intramedullary nails and transfixing screws. All twenty-eight fractures were nailed in static fashion initially. Twelve patients were randomly chosen and they were changed from statlc fixation to dynamic fixation at average 16 weeks after surgory. The purpose of this study was to compare the bone healing rates, clinical results, and postoperative complication between the static fixation group and dynamiaation group. The results were as follows ; 1. According to Winqulst-Hansen classification : 9 cases were type I : 7 cases, type II : 6 cases, type III : 4 cases, type IV and : 2 cases, type V. 2. All sixteen fractures, treated by static fixation achieved bony union(mean union time : 21 weeks). 3. Of twelve fractures with dynamization, eleven fractures were united (mean union time, 19 weeks). 4. Postoperative complications were limb shortening (4 cases : mean 0.7cm), nail breakage (1 case) and nonunion(1 case). We consider interlocking intramedullary nailing is the treatment of choice for closed or open femoral shaft fractures and dynamization is not an essential procedure for fracture healing.