In order to pursuit the leucopoetic functions in the bone marrow of the patients with silicosis, grawth ability of the cultured bone marrow and functions of the cells in the bone marrow were observed on the clinical tissue culture method of the bone marrow in the silicosis patients. Following results were obtained. 1) The growth ability of the cultured bone marrow were demonstrated within normal limits in the grawth area and cell density in the patients with chest x-ray findings of I-II and III type, while somewhat depressed in IV type. Definite depression was obrerved in C of IV type. This tendency was mostly remarkable in the findings of the cell density. 2) Functions of the bone marrow cells such as wandering velosity and phagocytic function of the india ink of the neutrophilic leucocytes were normal in I-II anb III type of the chest x-ray, and almost normal in A and B of IV type, while inhibition of the function was observed in C of IV type,