We performed 22 reconstructions by allografts in patients with pelvic sarcoma: 14 Ewing's sarcomas, 7 chondrosarcomas, and 1 osteosarcoma. All patients with Ewing's sarcoma and osteosarcoma received chemotherapy. No patients with chondrosarcoma had adjuvant treatment. 12 reconstructions were iliosacral arthrodesis after resection of an ilium tumor, 1 was iliofemoral arthrodesis and 9 were pelvic reconstructions with total hip prosthesis after resection of an acetabulum tumor. In the surviving patients, the mean length of follow-up was 4 (2-6) years. 2 allografts fractured and 8 allografts developed an infection. The infection was commoner in patients who had chondrosarcomas, large tumors, and a long operation time. Neither chemotherapy nor radiotherapy increased the infection rate. All infected allografts had to be removed.