The purpose of this study was to evaluate the long-term results of rectus femoris transfer in cerebral palsy children with stiff-knee gait. Thirty-eight affected limbs in 24 children were evaluated preoperatively and 1 year postoperatively by gait analysis, with 26 limbs in 18 patients having final study, averaging 4.6 years postoperatively. Functional ambulatory status was evaluated based on Hoffer's criteria on ambulation. There were statistically significant improvements of 9.8 degrees in maximum swing-phase knee flexion and 7.0 degrees in total range of knee motion at 1 year, with a small loss of knee extension in stance. At final gait analysis, the improvement in the swing-phase knee flexion was maintained, but improvement in total range of knee motion was decreased. There were no significant changes in temporal parameters. Improvement in swing-phase knee flexion and foot clearance after rectus femoris transfer was associated with loss of knee extension at long-term follow-up. Hamstring lengthening in patients who develop excessive stance-phase knee flexion may be necessary.