Seventy-eight patients who had undergone bilateral derotational osteotomy of the femur for medial femoral torsion were reviewed to evaluate the procedure and to determine the frequency of postoperative complications. Patients averaged 6 years of age at the time of the procedure; girls predominated. Before derotational osteotomy, the mean hip rotation measurements were 84 degrees medially and 16 degrees laterally; following the procedure, mean hip rotations were 41 degrees medially and 51 degrees laterally. Medial femoral torsion was reduced from 54 degrees mean to 14 degrees. Balancing these favorable results, however, was a 15% risk of complications; 12 of our patients had problems associated with loss of fixation, errors in amount of correction, fractures, heel ulcer, or infection. Derotational osteotomy is only justified for the child with a persistent severe disability from medial femoral torsion. The parents should be aware of the significant risks and the lack of evidence for any long-term adverse effects if moderate MFT is left uncorrected.