This retrospective study compares Pavlik harness application versus spica casting for the treatment of children under 1 year of age with a femoral shaft fracture. The clinical and radiographic outcomes of 24 patients treated in a Pavlik harness were compared with 16 patients treated in a spica cast. The average age and weight of the two groups were significantly different, but there were no differences in radiographic outcomes between the Pavlik and spica cast groups. Approximately one third of all spica patients had a skin complication that added an additional risk to the patient. There were no similar complications in the Pavlik group. There were no differences in the outcome of the fractures in the two groups. The authors believe that all children under 1 year of age with a femoral shaft fracture are candidates for treatment with a Pavlik harness.