A registry of haematopoietic malignancies was established on January 1, 1980 in order to accurately determine the incidence and epidemiological features of these diseases in the department of Côte d'Or (population 478,000). Over five years (1980-1984), 704 new cases were recorded. The crude incidence rates were 32.7 per 100,000 for males and 24.9 per 100,000 for females. The corresponding age standardized rates were 26.4 and 16.7. The sex ratio was 1.6:1. In males, chronic lymphocytic leukaemias were the most common haematopoietic malignancies, followed by non Hodgkin's lymphomas, acute leukaemias and multiple myelomas. In females, multiple myelomas and acute leukaemias preceded non Hodgkin's lymphomas and chronic lymphocytic leukaemias. For men and women, the risk of haematopoietic malignancies was higher in urban areas than in rural areas. Compared to population based registries in other countries, incidence rates are among the highest reported and are particularly high for chronic lymphocytic leukaemia.