With the Purpose to clarify the characteristics in each type of leukemia, the author analyzed the 822 ca es of leukemia collected from the death certificates in the Chugoku-Shikoku District (excluding Hiroshima Prefecture) during the period from 1951 to 1957. The results are as following. a. Those simply diagnosed as leukemia occupy 25 per cent. Of the classified cases, the mumber of tne acute type is decidedly greater than the chronic type, on the other hand, they come in the descending order of the myelogenous, lymphocytic, and monocytic leukemia in their frequency. In any acute and chronic type, the lymphocytic leukemia is less than myelogenous leukemia in the absolute number, but relatively speaking, the proportion occupied by the acute type is greater. b. The rate of incidence surveyed from the average age is in the ascending order of tne acute lymphocytic leukemia, acute myelogenous, chronic mylogenous, and chronic lym phocytic; and the acute type and lymphocytic leukemia are greater in younger persons whereas the chronic and myelogenous ones are greater in advanced age. C. As for the peculiarity with respect to occupation, since the majority unemployed group are youner persons, the acute type and lymphocytic leukemia can be frequently encountered among the unemployed. d. The cases simply diagnosed as leukemia are on the decrease, whereas those diagnosed as the acute type, especially the myelogenous and monocytic ones are increasing each year. e. The time of death from leukemia has no fixed relationship with season of the year. f. Of those suffering from the acute type of leukemia 95.9 per cent die within six months after the onset of disease, and 92.8 per cent of those with the chronic type die after the lapse of three months. The mean duration of life in the chronic type is about one year. In addition, the duration of survival tends to be shorter in the lymphocytic ones while longer in myelogenous ones. g. From the geographical standpoint the Shikoku coastal region facing the Pacific differs greatly from other districts in that there are more unclassified leukemia cases, and of the classified cases, myelogenous ones are rare while lymphocytic ones are more numerous. Between the urban and rural districts threr is no difference worthy of mentioning.