The actual debate on temporal or regional clustering of childhood leukaemias includes an intensive discussion, whether or not the observed patterns of frequency distribution are governed merely or mainly by random processes. With the "Information System on Cancer Mortality and District Characteristics (IKK)" the Cumulative Mortality Rates of childhood leukaemias (up to age 15) are determined for the single district authority units (Kreis) in the Federal Republic of Germany (old Laender) between 1975 and 1990. The frequency distributions of the mortality rates as well as the dependencies on population density are analysed. No statistical significance for a deviation from the corresponding mere random distributions could be revealed.