PURPOSE: Neonatal neuroblastoma (NBL) is the most common malignant tumor in neonates, but there have been few studies about it. The purpose of this study was to investigate the clinical features of NBL and to compare prenatal and postnatal diagnosed groups. METHODS: Nineteen patients who were diagnosed with NBL prenatally or within 28 days after birth from February 1986 to February 2013 in Seoul National University Hospital were enrolled in the study. The patients were categorized according to the International Neuroblastoma Staging System (INSS) and Children's Oncology Group (COG). Retrospective medical-record reviews were performed on these patients. The operative date, complication, pathological stage, and overall survival of the prenatally diagnosed group and the postpartum diagnosed group were compared. RESULTS: Tumor was detected via prenatal ultrasonography in 8 patients (42.1%), and 11 patients (57.9%) were diagnosed within 28 days after birth. Based on INSS, the patients were divided into the stage I (n=8), stage II (n=1), stage III (n=3), stage IV (n=4), and stage IVs (n=3) groups, respectively. Based on COG, on the other hand, the patients were divided into the low-risk (n=8), intermediate-risk (n=8), and high-risk (n=3) groups. The postoperative complication rate was 29%. One patient died from complications from chemotherapy. The other 18 patients' mean follow-up period was 77.7 months. The differences between the postoperative complication rate, proportion of early-stage tumor, and overall survival of the prenatal and postnatal groups were not statistically significant (p=0.446, p=0.607, p=0.414). CONCLUSION: NBL showed favorable outcomes but relatively higher postoperative complications. There seem to be no significant statistical differences in the postoperative complications, proportion of early-stage tumor, and overall survival between the prenatally diagnosed group and the postpartum diagnosed group.