Nineteen patients with advanced malignant tumors, less than 20 years old were treated with intensive chemotherapy (vincristine 2 mg/m2 i.v. and adriamycin 60 mg/m2 i.v. on day - 7; cyclophosphamide 45 mg/kg i.v. on days -6 to -3), total body irradiation (TBI, 600 rads on day -1) and autologous bone marrow transplantation (ABMT, day 0). Prior to this procedure induction of complete or partial remission by conventional therapy was attempted. Ten patients had intra-abdominal non-Hodgkin's lymphoma (NHL); three, yolk sac tumor; three, Ewing's sarcoma; and three, neuroblastoma. The supportive care included reverse isolation, immunoglobulin 400 mg/kg i.v. q 2 weeks, cotrimoxazole per os, and cell support as needed. No correlation between the bone marrow dose and the time of hematological reconstitution could be established. Five of seven patients with intra-abdominal NHL stage III (transplanted in first remission) are surviving disease-free for 5+, 5+, 20+, 23+, and 35+ months after ABMT. None of three patients with intra-abdominal NHL stage IV is surviving (two of them were transplanted in second remission). One of three patients with yolk sac tumor is surviving disease-free for 27+ months. There are no survivors among the patients with Ewing's sarcoma and neuroblastoma. Only one of 19 patients was lost due to therapeutic complications, while 12 died due to tumor. Regarding treatment results for advanced intra-abdominal NHL, the procedure described here is comparable to the best conventional regimens. In vitro methods for tumor cell eradication in the collected bone marrow might further improve the results of ABMT.