Two hundred and thirty-nine patients with Ewing's sarcoma were treated at our institution between 1972 and 1987: 42 of these had lesions in the pelvis, 29 were in the wing of the ilium or involved the sacroiliac joint (type I), 5 were periacetabular (type II), and 8 were in the anterior pelvic arch (type III). Radiotherapy alone was used for the primary lesion in 11 cases, adjuvant chemotherapy in 20 and a neoadjuvant protocol in 22. The overall disease-free survival at a mean follow up of 34 months was 19%. There was no difference in survival related to age or the site in the pelvis, none in disease-free survival with adjuvant and neoadjuvant chemotherapy, or in the incidence of local recurrence and metastases in these two groups. Similarly, there was no difference in disease-free survival between operative treatment, with or without radiotherapy, and radiotherapy alone. There was a slight trend towards better local control of the disease in the former group compared to the latter, although this difference was not statistically significant. Our conclusion is that treatment needs to be planned for each individual patient.