Bleomycin was administered to 14 patients with malignant lymphoma (5 cases of reticulum cell sarcoma, 6 cases of Hodgkin's disease, 1 case of lymphosarcoma and 2 cases of histologically unclassifed type), and also given to 9 patients with leukemia. In 10 of the 12 cases of malignant lymphoma treated with Bleomycin alone, enlarged lymph nodes clearly schrank following treatment, and a remarkable effect appeared promptly in 5 of them. In the other 2 cases treated with Bleomycin and fibroblast-inhibiting agents, there occurred both tumor regression and improvement of host conditions. The latter agents appeared to prevent. the development of pulmonary complications. In some cases of leukemia treated with Bleomycin, the leukocyte counts were decreased. Hematopoietic function of bone marrow was not disorderd by Bleomycin, but attention shoud be paid to its side effects for the lungs. The clinical experiences with Bleomycin indicate that the drug might well be used as a remission inducer, and expected to improve the chemotherapy in the treatment of malignant lymphoma, but its life prolongation effect in leukemic cases needs further observation.