Medical records of 59 patients with cerebral palsy were reviewed retrospectively to evaluate results of tendoachilles lengthening. Surgical lengthening resulted in highly significant (p < 0.0001) initial average gains in dorsiflexion compared with baseline. These average improvements maintained their statistical significance for seven years postoperatively. The arc of motion was not significantly different postoperatively. The initial ambulatory level was improved in 55% of the patients and maintained in the remainder. However, 14 ankles (11.9%) in eight patients (13.6%) required repeat tendoachilles lengthening during the study period, primarily after gastrocnemius procedures. Calcaneus deformity occurred in 1.7% of the surgically treated ankles. To evaluate the potential for spontaneous improvement over time in fixed equinus deformity, the records of a group of 68 additional cerebral palsy patients were reviewed. Patients treated nonoperatively despite two examinations that demonstrated fixed lack of dorsiflexion, while not representing a true control group, showed no spontaneous improvement in equinus deformity through seven years postoperatively.