A retrospective review of all cerebral palsy (CP) patients with resistant or recurrent knee flexion contractures treated with serial stretch casting was performed. The protocol consisted of sequential wedging (5 degrees per week) of fiberglass casts until maximum knee extension had been achieved. Measurements were made prior to the initiation of casting, at completion of the casting, and at 1 year after the casting. Forty-six subjects, with 75 involved extremities, met the study inclusion criteria. Mean age at the time of initiation of casting was 12.7 years. Using radiographic measurements, the mean initial degree of knee flexion contracture was -17.6 degrees. At the completion of casting, the mean knee flexion angle was -8.1 degrees. The mean duration of casting was 30 days. At 1 year after completion of the casting, the mean knee flexion angle was -12.2 degrees. Initial correction to within 10 degrees of full extension was achieved in 76\% of extremities. Age less than 12 years and initial flexion contracture of less than -15 degrees were statistically significant factors related to maintenance of correction at 1 year. Complications included soft tissue compromise in 13 extremities (17\%), transient neurapraxia in 9 extremities (12\%), and tibial subluxation in 1 extremity (1\%). Serial stretch casting was successful in correcting resistant knee flexion contractures in the majority of cases. Casting was less effective in teenagers and those with larger contractures. Complications were minimized by proper casting technique and controlled rate of correction.