This study constitutes the second volume of the updated national estimates of cancer incidence. Following solid tumors (Part 1), this update focuses on the incidence of malignant hematological diseases, estimated for the first time in France by histological subtype. This approach reflects advances in understanding, both etiologically and in terms of the clinical and prognostic aspects of these diseases, which are now considered distinct. Consequently, incidence is estimated directly using a model of incidence within the registry area rather than using the incidence-to-mortality ratio traditionally employed, as mortality data coding does not allow for such precise differentiation among the various malignant hematological diseases. The study focuses on new cases of malignant hematologic diseases diagnosed between 1975 and 2009, recorded by 14 registries with at least five consecutive years of data. Fifteen types of malignant hematologic diseases are studied. In 2012, the number of new cases of malignant hematological diseases in mainland France is estimated at 35,000 (19,400 in men and 15,600 in women). The four most common sites in 2012 were multiple myeloma/plasmacytoma (4,888 new cases), chronic lymphocytic leukemia/lymphocytic lymphoma (4,464), diffuse large B-cell lymphoma (4,096), and myelodysplastic syndromes (4,059). Trend analysis distinguishes between malignant hematologic diseases with a standardized incidence rate decreasing globally in both sexes (chronic myeloproliferative syndromes excluding chronic myeloid leukemia) and those with a rate increasing by 1 to 2% annually in both sexes (multiple myeloma/plasmacytoma, acute myeloid leukemias, chronic lymphocytic leukemia/lymphocytic lymphoma, follicular lymphoma, marginal zone lymphoma, classical Hodgkin lymphoma, myelodysplastic syndromes). Distinguishing incidence rates according to the main histological types of malignant hematologic diseases significantly refines our understanding of these diseases and allows us not only to track trends for each type of malignant hematologic disease over time but also to generate etiological hypotheses or provide opportunities for diagnostic and therapeutic comparisons. (R.A.)