Although infants with stage 4 neuroblastoma (NB) usually have a good prognosis, metastatic relapses after 1 year of age and amplification of the N-myc oncogene are established poor prognostic factors. In order to improve the survival of patients with such high-risk factors, we performed consolidation with a busulfan (600 mg/m2)-melphalan (140 mg/m2)-containing regimen followed by autologous stem cell transplantation (SCT). From 1986 to 1998, 12 patients were treated according to this strategy. Their median age at diagnosis was 9 months (1-11). Consolidation was performed after a metastatic relapse in five children, because of persistent bone metastases in one and as first-line consolidation in six patients whose tumor exhibited N-myc amplification. The 5-year EFS rate is 64. 5% (36-85%) with a median follow-up of 92 months (20-126). One toxicity-related death occurred in a very heavily pretreated patient. Hepatic veno-occlusive disease was the major side-effect that occurred in nine of 12 children. This busulfan-melphalan combination appears to dramatically improve the prognosis of these high-risk infants with metastatic NB. Given its high toxicity, indications for this consolidation must be restricted to high-risk infants and a lower dose of busulfan (480 mg/m2) is recommended in children weighing less than 10 kg. Bone Marrow Transplantation (2000) 25, 937-942.