Twenty-one children with high-risk Ewing's tumor received high-dose chemotherapy with a PBSCT. Aim of the study was evaluation of efficiency and safety of this procedure. All but three patients have meta-static disease at presentation. There were 11 females and the median age at diagnosis was 12 yr (range 4.5-18 yr). Megachemotherapy consisted of melphalan 140 mg/m2/busulfan 16 mg/kg in 12 patients, melphalan 140 mg2/treosulfan 10.0 g/m2 in two patients and melphalan with other drugs in seven patients. Eight of 11 patients transplanted in CR survived with a median follow-up 24 month (range 14-60) and probability of 2-year OS is 0.68 and DFS is 0.63. There was no severe regimen-related toxicity in this group. Children transplanted without remission died: Two of them due to transplant related causes and eight had progression of disease in a median time 7 month after PBSCT. Megachemotherapy with PBSCT is a safe procedure in children with Ewing's sarcoma in remission. Autologos transplantation in children with metastatic Ewing's sarcoma seems to improve their outcome. Patients with Ewing's sarcoma, resistant to conventional therapy and with recurrent disease did not benefit from megachemotherapy. New approaches such as anti-tumor vaccination or using of imatinib are reasonable to introduce in patients with relapsed or resistant to therapy Ewing's tumor.