Seventy-eight diaphyseal femur fractures in 77 children were stabilized with flexible intramedullary nails. The patients ranged in age from 2 + 9 to 18 years. All patients had open femoral growth plates at the time of fixation. Eleven percent of the fractures had an average varus or valgus malalignment of 6 degrees. Eight percent of the fractures had an average anterior or posterior malalignment of 8 degrees. Eight percent of the patients had a rotational malalignment that averaged 8 degrees. Sixty-eight percent of the children had equal leg lengths at follow-up. There were four unscheduled reoperations, but no major complications; all fractures united. The results obtained using flexible intramedullary nails for the stabilization of select pediatric diaphyseal femur fractures are comparable to nonoperative methods of treatment, but with less disruption to family life and a shorter hospitalization.