The new WHO classification is based on the principles of REAL classification of lymphoma and expands to myeloid, mast cell and histiocytic/dendritic neoplasms. The distinct diseases are defined according to a combination of morphology, immunophenotype, genetic features, and clinical syndromes, and the cell origin is postulated. Lymphatic leukemia is included in lymphoma. The lymphoid malignancies are grouped into B cell lymphoma, T/NK cell lymphoma and Hodgkin lymphoma, and the myeloid neoplasm are grouped into 4 categories; chronic myeloproliferative diseases(chronic myelogeneous leukemia, polycythemia vera, chronic idiopathic myelofibrosis, essential thrombocythemia etc.), myelodysplastic/myeloproliferative diseases (chronic myelomonocytic leukemia, juvenile myelomonocytic leukemia etc.), myelodysplastic diseases(perfactory anemia, refractory anemia with ringed sideroblasts etc.) and acute myeloid leukemia.