Sixty-five children with neuroblastoma without evidence of distant metastases underwent initial tumor resection. Seventeen with no evidence of lymph node involvement in whom tumor resection was complete (Group 1) received no further antitumor therapy. One child died postoperatively; disease recurred in the bone marrow of one child at 52 months, the child subsequently died. Fifteen were alive without disease, giving an 82% actuarial five year survival. Forty-eight children with minimal residual tumor and/or regional lymph node involvement (Group 2) received two 5-day courses of Peptichemio (1.2 mg/kg/d) and the 29 children in this group who were older than 1 year of age at diagnosis were randomized to receive either radiotherapy to the tumor bed in addition or no radiotherapy. In Group 2, ten of the 48 have relapsed: six of 17 with initial lymph node involvement, three of four with tumor rupture at operation, and one of eight with tumor extension to the intervertebral foramen. No relapses were seen in the 19 children with minimal residual tumor confined to the tumor bed. Only one of the 18 Group 2 children who were younger than 1 year of age at diagnosis relapsed. Of the 29 Group 2 children who were older than 1 year of age at diagnosis, five relapses occurred in the 14 who received radiotherapy and four relapses in the 15 who did not receive radiotherapy. All six children with disseminated relapse died. Actuarial 5-year survival in Group 2 is 87%, and actuarial relapse-free survival, 76%.