Since 1980, a nationwide registry of childhood malignancies has been established in the Federal Republic of Germany. The registry combines features of a population-based and a hospital-based registry. Basic registry data are complemented and validated by data from all ongoing clinical trials in paediatric oncology. Descriptive analyses are presented for the first 13 years of operation of the registry. In addition, time trends and regional variations of incidence within the Federal Republic of Germany are shown. A brief description of completed and ongoing registry-based epidemiological studies is given.