Hemipelvectomy was performed in 50 patients with malignant neoplasms of the upper part of the thigh and pelvis. Although not technically difficult, the operation is associated with considerable blood loss. Postoperative complications are frequent, the greatest morbidity resulting from skin flap necrosis. Symptomatic phantom limb is as occasional late problem. Of 37 patients resected for cure prior to 1969, 14 were alive five or more years postoperatively. Five of these long-term survivors subsequently died of metastases. Patients with fibrosarcoma and chondrosarcoma had the best survival. Six other patients underwent palliative hemipelvectomy for intractable pain, with gratifying results. Hemipelvectomy is an important, useful operative procedure in selected patients.