Femoral shaft fractures are among the most common fractures of the lower extremity in children. There are several different options for treating femoral-shaft fractures in children, including skeletal or skin traction, early or immediate application of a hip spica cast, closed reduction and minimally invasive plate osteosynthesis, external fixation, plate fixation, and internal fixation with the insertion of intramedullary nails. Aim of the work: The aim of this study was to evaluate and compare the outcome of surgical interference with flexible intramedullary nailing and the traditional treatment method, hip spica casting, in treating pediatric femoral shaft fractures.Methods: 30 patients with femoral shaft fracture were included in this study; 15 patients were treated with 2 retrograde FIN and 15 patients were treated with early hip spica casting, there was no statistically significant difference between both groups preoperatively in all items, we followed up all patients for a period of 6 months, patients were followed up for coronal and sagittal angulation, malrotation, limb length discrepancy, skin complications, knee range of motion, time of full union and time of full weight bearing.Results: Fracture union and full weight bearing with return to normal activity were significantly earlier in FIN group, angulation in both the coronal and sagittal planes was significantly higher in the spica group than in the FIN group, other followed up factors (malrotation, LLD, skin complications, knee range of motion) were not found to be statistically significant in our study.Conclusion: The present study supports the treatment of femoral shaft fractures in children aged 4-12 years with FIN, as it hastens fracture union, reduces the rate of malunion, and allows earlier, weight bearing, rehabilitation and return to normal activity.