Twenty-two patients underwent hindquarter amputation with curative intent for malignant or locally aggressive tumors of the pelvis (21 cases) or proximal thigh (one case). In all cases, the ilium was resected, and in seven cases an osteotomy of the sacrum was done to achieve negative surgical margins. Only six wounds healed without complications. The worst wound problems occurred in patients requiring ligation of the common iliac vessels and in those requiring a sacral osteotomy. Twelve patients have died of disease, two are alive with extensive pulmonary metastases, and one remains well after excision of a local tumor recurrence. Thirteen of 14 patients with high grade sarcoma had metastases develop, compared with only one of eight patients with low grade sarcoma. Eight patients (all with high grade sarcoma) died within 1 year of surgery. Seven patients have remained disease free at a mean of 39 months after surgery. Given the poor prognosis and high morbidity after amputation in high grade sarcoma, the authors think that consideration should be given to pursuing nonoperative management in patients with large, high grade sarcomas and significant medical extension to the sacroiliac joint or sacrum.