In the hospitals of the Tohoku Neuroblastoma Study Group (TNBSG), treatment for children with advanced neuroblastoma (NB) was intensified in the mid-1990's with the introduction of myeloablative therapy (MT) with stem cell transplantation (SCT) including the use of autologous peripheral blood stem cells (PBSC) and bone marrow transplantation (BMT). In this report, we examined whether the intensified therapy improved the outcome of children with advanced NB (age> 12 months) who were diagnosed between 1991 and 1997. Patients were 36 children (23 boys and 13 girls) with an average age of 3.4 years (range; 1 to 14 years). Six of them had stage III disease, and the other 30 had stage IV. They were treated initially with induction chemotherapy, surgery, and post-operative chemoradiotherapy, after which 17 of them continued further chemotherapy and the other 19 received MT/SCT (18 with PBSCT and 1 with BMT). Progression-free survival (PFS) rate at seven years from diagnosis was 43.5% for all patients, 66.7% for stage III patients and 38.2% for stage IV patients. The difference between stage III and IV patients was not significant. Among the 30 patients with stage IV disease, PFS at seven years was significantly higher in the 19 patients who received MT/SCT (55.6%) than in the 11 patients who did not receive it (12.5%). There was no difference in clinical and biological risk factors between these two groups, except for the proportion of patients with favorable response to initial therapy (36% and 80% for patients without and with MT/SCT, respectively). Furthermore, the proportion of patients with N-myc amplification was significantly higher in patients with progressive disease (PD) after MT/SCT than in those in CR after MT/SCT. The results of this retrospective study of children with advanced NB suggest that therapy intensification involving MT/SCT might result in lengthened survival time for patients with stage IV disease, and that post-transplant PD remains a risk for patients with high levels of N-myc amplification.