By the registry of hematopoietic malignancies in Côte d'Or we studied the 177 cases of myeloproliferative disorders diagnosed between 1980 and 1986, divided into 4 groups: chronic myelogenous leukemia, idiopathic myelofibrosis, polycythemia vera, essential thrombocythemia. The global standardized rates based on the world population were 3.5 per 100,000 in men and 1.9 in women (sex ratio = 1.8). The mean age for myeloproliferative disorders was 61 +/- 16 years. Incidence was slightly higher in urban than in rural areas (NS). The most common means of detection were routine hemogram, fatigue and thrombosis. Five-year survival curves showed large differences in prognosis, from 30% for chronic myelogenous leukaemia to 83% for polycythaemia vera.