Two patients with chondrosarcoma of the periacetabular region were treated by local resection and reconstruction of the pelvic ring and hip, implanting a Charnley-Mueller total hip replacement and reconstituting the pelvic ring with cement reinforced by Küntscher rods and heavy Kirschner wires. The first patient, in whom adequate resection was accomplished, was well five years later and was able to walk with a mild lurch and without a cane except when walking long distances on rough ground. Despite a fall causing a fracture of the ipsilateral tibial plateau at two years and a fatigue fracture of the ipsilateral ischium which healed at 4.5 years, the implant had remained intact. In the other patient, for whom hemipelvectomy was advised but who refused it, the resection was not adequate and although he was able to walk with a cane for short distances postoperatively, he died of metastases at two years. Based on these two cases, it would appear that reconstruction of the pelvic ring and hip may be feasible in a few very carefully selected cases of periacetabular tumors.