During the time period 1990 to 1994 the mean incidence of pediatric brain tumors in Switzerland reached 2.78 new cases per 100,000 children under 16 years of age per year. In the same time period 33 children (18 male, 15 female) were newly diagnosed at the University Hospital of Berne with a tumor located in the posterior fossa. Ten (31%) had a medulloblastoma, nine (27%) an astrocytoma, six (18%) a brain-stem glioma, four (12%) an ependymoma, and four (12%) had other tumor types. Besides typical signs and symptoms of increased intracranial pressure, cranial nerve palsies or visual problems were frequently found (in 70% and 30% of the patients, resp.). The median time interval between the first symptoms and the definite diagnosis was four months. Central in the therapeutic approach remained the neurosurgical removal of the tumor, which was realized in 85% of the cases. As adjuvant weapons, radiotherapy and/or chemotherapy (in 45% and 48.5%, resp.) were used with curative aims. Globally 16 of the 31 evaluable children 51%) survived disease-free at the time of evaluation with a median survival of 42 months. The two-year survival rates were 83% for astrocytoma, 50% for ependymoma, 46.5% for medulloblastoma and 40% for brain-stem glioma. These observations emphasize the prognostic significance of histology in pediatric brain tumors.