Fourteen children (mean age 11.3 y) with a closed comminuted femur shaft fracture were surgically treated by biologic internal fixation using a bridging plate. The fractured area was not opened. After indirect reduction, internal fixation was made by a bridging plate through two small incisions, exposing the lateral aspects of proximal and distal fragments. The mean complete radiographic healing time was 12.4 weeks. After a mean follow-up period of 4 years, all patients were satisfied with the clinical outcome. The mean radiographic torsional deformity of the injured limb with respect to the uninjured limb was 4.5degrees. A residual radiographic frontal or sagittal plane angulation of more than 10degrees was seen only in one patient. It was concluded that biologic internal fixation by bridge plating was an effective surgical treatment method for the closed comminuted fractures of the proximal and distal thirds of the femur shaft in children.