BACKGROUND: Patients with cerebral palsy (CP) are at risk for hip arthrosis secondary to the loss of joint congruity. QUESTIONS/PURPOSES: We asked whether THA relieved pain, improved function, and provided durable improvements. METHODS: We retrospectively identified 56 patients (59 hips) with CP who had THAs for painful hips. Chart review determined the preoperative, postoperative, and current functional levels. All patients or caregivers completed a questionnaire, including a modified Gross Motor Function Classification System mobility scale and qualitative reports of pain and satisfaction. Pain levels were measured on a visual analog scale at three times: preoperative, postoperative, and current. The average age of the patients at the time of surgery was 30.6 years. Minimum followup was 2 years (average, 9.7 years; range, 2-28 years). RESULTS: Pain relief was obtained in all patients. All patients returned to preoperative function (59) and 52 patients returned to prepain functional status (88%). Seven patients underwent acetabular component revisions, and two patients had a femoral stem component revision. The 2-year implant survival was 95%, and 10-year survivorship was 85%. CONCLUSIONS: THA can provide durable relief and improved function in patients with CP with severe coxarthrosis. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.