In order to observe the erythropoetic functions in the bone marrow of the patients with silicosis, roller tube culture of the sternal bone marrow and sideroblast of the silicosis patients were carried out. Following results were obtained. 1) In observation in the roller tube culture, the erythropoetic functions were revealed the most activated status in III type of the cheat x-ray findings. The grade of their activations were followed hypofunctionally by in A and B of IV type, and in C of IV type of the chest x-ray. 2) The sideroblasts were shown to be decreased in number mostly in III type of the chest x-ray and tended to decreasing in A and B in IV type, while they were increased in number in I and II and C of IV type which were shown somwhat increased than the average value of the normal healthy persons. But these latter findings ranged within normal limits. 3) Above findings are strongly suggested that the erythropoetic fnnctions are normal or slightly activated in I and II type of the chest x-ray findings and definitely acticated in III and A and B of IV type and normal or rather inhibited in C of IV type.