Objective: To investigate the age, gender, location and pathologic diagnosis of brain tumors in pediatric patients (less than 16 years old), we reviewed 677 patients who were operated on at the Department of Neurosurgery, Seoul National University Hospital (SNUH) during the period from January 1959 to June 2000. Patients and methods: Only tumors for which pathologic specimens were available were included. Tumors of bone origin, purely extradural mass, nontumorous cystic lesions, and vascular malformations were excluded. The mean age of the 677 patients was 7.8 years and the gender ratio (male-to-female ratio), 1.4:1. Supratentorial tumors (60.0%) were more common than infratentorial tumors (39.1%). Pathological examination showed that the most common tumors were astrocytic tumors (25.7%), medulloblastomas (17.9%), craniopharyngiomas (12.0%), germ cell tumors (11.2%), supratentorial primitive neuroectodermal tumors (ST-PNETs) (5.5%), and neuronal tumors (5.2%). Choroid plexus tumors and ependymal tumors occurred more frequently in early childhood, while pituitary adenomas and nonteratomatous germ cell tumors occurred more frequently in older children. While most tumors were more predominant in males, oligodendroglial tumors and pituitary adenomas were more predominant in females. Conclusions: The relative incidences of germ cell tumors, neuronal tumors, and oligodendroglial tumors increased after the introduction of magnetic resonance imaging (MRI). In contrast, the incidence rates of medulloblastomas and ependymal tumors decreased.