Background: Tumor specimens from 19 patients with untreated primary neurobtastoma were assayed for amplification of the N-myc oncogene to determine whether N-myc gene amplification correlated with clinical outcome. Methods: Tumor DNA was extracted from 3 fresh frozen tissues and 16 paraffin embedded samples. N-myc amplification was analyzed by hybridization with the radiolabeled probe pNB-1. Results: Amplification(over 3 copies) of the N-myc gene was found in 8 of the 19 patients(42%). Amplification was not found in 2 stage 1, but it was found in 1 stage Ⅱ, 1 of 6 with stage Ⅲ, and 6 of 10 wish stage IV tumors. 5 of 11 patients whose tumors had 1 copy number are alive without disease, while only 3 of 8 patients whose tumors had more than 3 copies are alive and 2 have a recurrence. Conclusion: These results suggest that the genomic amplification of N-myc seems to be a prognostic indicator and this gene may play a role in the progression of certain neuroblastoma.