Background:Femoral shaft fractures are one of the most common fractures of the lower extremities in children. Although many approaches and options are available for their treatment, the most appropriate treatment option for school going children is still debatable.Objective:This study investigated the efficacy, safety, and outcome of surgical intervention with Elastic Stable Intramedullary Nailing (ESIN) in 3–12-year-old children with diaphyseal femoral fractures and compared them with those of conservative management.Methods:In this prospective study, 41 children with diaphyseal femoral fractures were recruited between April 2013 and April 2016. The fractures were divided into two equal groups: one treated with ESIN, and the other with early spica casting or noninvasive traction followed by hip spica casting. Demographic data, clinical information, and serial radiographic findings were collected and compared between the two groups. Flynn’s scoring criteria pertaining to time to union, assisted weight bearing, independent ambulation, return to school, and complications were applied. Fischer’s exact test was used for statistical analyses.Results:Compared with spica casting-treated fractures, ESIN-treated fractures healed faster with lower average time to assisted weight bearing, independent ambulation, and return to school. Hip spica-treated children had a higher rate of major complications than ESIN-treated children. At 1-year follow-up, higher limb length discrepancy was reported in hip spica-treated children than in ESIN-treated children (P< 0.001).Conclusion:ESIN is a safe and effective approach for treating femoral shaft fractures in children; it provides better functional and radiographic outcomes than spica casting and can be used in preschool-age children.