Dysmyelopoietic syndromes cover sideroblastic or nonsideroblastic refractory anemia with or without excess of blasts, subacute or chronic myelomonocytic leukemia. The evolution of 193 patients was studied with regard to the initial hematologic picture. A certain number of variables of prognostic value have then been isolated: excess of marrow blasts (more than 5%); presence of circulating blasts or karyotypic anomalies; reduction in the number of polymorphonuclear leukocytes (less than 1.043 10(9)/l, of monocytes (less than 0.136 10(9)/l), of platelets (less than 140 10(9)/l), of in vitro granulopoietic progenitors (less than 5 per 10(5) nucleated cells plated), of erythrocytic incorporation of 59Fe at day 14 (less than 12%), of hemoglobin level (less than 92 g/l); previous exposure to radiation or chemotherapy; early hemolysis in 51Cr-labeled erythrocytes study; marrow heterogeneity in histology; less than 20% of ringed sideroblasts. The correlation between these variables and adjustments related to the length of survival and the order of magnitude of the critical level of the log-rank test show that the most significant variables in descending order are: excess of marrow blasts, neutropenia, thrombopenia, presence of circulating blasts, the type of erythropoietic insufficiency, and decrease of in vitro growth.