An epidemiologic investigation of true neoplasms of the central nervous system in fetuses and infants in the German Democratic Republic (GDR) was undertaken. Since all fetal deaths and all deaths in the first year of life are subject to a full postmortem examination and since all cancer cases or deaths are reported to a central registry, the prerequisites for a valid assessment of the incidence of these tumors are present. During the years 1960-1979, 55 histopathologically verified tumors of the central nervous system were identified in the GDR, a frequency of approximately 1.1 per 100 000 births. Unexpectedly, medulloblastoma (13 cases) was the most frequent tumor type.