PURPOSE: To traditional treatment of pediatric femoral shaft fracture has been a traction and spica cast application. But flexible intramedullary nail fixation has been introduced as an alternative to other treatment modalities. With this in mind, we analyzed the clinical and radiologic results of flexible intramedullary nail fixation of pediatric femoral shaft fractures. MATERIALS AND METHODS: We analyzed 12 patients (13 cases) who were treated with flexible intramedullary nail and followed up for at least 6 months at the department of Orthopedic Surgery, Inje University Ilsan Paik Hospital since May, 2002. RESULTS: In all 12 patients (13 cases) involving 1 case with reoperation because of reduction failure, average duration of bone union was 12.6 weeks. There were no considerable complications except mild post-op knee pain and limitation of motion. CONCLUSION: In spite of relatively short term study, a flexible intramedullary nail fixation seems to be a useful method without serious complications on pediatric femoral shaft fracture. However, in big or older pediatric patients, interlocking intramedullary nail fixation may be a better choice rather than a flexible nail fixation because of it's insufficient stability.