Background: Diaphyseal fractures of the femur (DFF) are common long-bone injuries in children and adolescents. DFF represent 1.5% of fractures in childhood. Objective: This study aimed to evaluate the clinical, functional and radiological outcome of femoral shaft fractures, which are managed by elastic stable intramedullary nailing (ESIN) in pediatric age 6-10 years. Patients and Methods: A prospective clinical randomized trial study was conducted on18 children underwent elastic stable intramedullary nailing (ESIN) for treating femoral shaft fractures at Orthopedic department, Zagazig University Hospitals during the period from April to December 2020. Plain X- rays of the femur Antero-posterior (AP) & Lateral (Lat.) views (from hip to the knee joint) was taken. Results: The time to surgery was 1.39 ± 1.12 days ranging from 1 to 6 days, the time till full union was 9.4 ± 1.76 weeks ranging from 7 to 12 weeks, more than half of the studied group (55.5%) ranged from 7 to 9 weeks and the time of full weight bearing was 9.6 ± 1.7 weeks ranging from 7 to 12 weeks, half of the studied group (50.0%) ranged from 7 to 9 weeks. So, the final outcome was 83.3% had excellent functional outcome, 11.1% of them had satisfactory functional outcome and 5.6% had poor functional outcome. 88.8% didn't have any complications, 5.6% of them had irritation and 5.6% had superficial infection. Conclusion: ESIN is the choice treatment for transverse and short oblique shaft fractures in patients aging from 6 to 10 years old.