A 75-year-old female was admitted to our hospital because of fever and hypotension. The peripheral blood showed 400 leukocytes/microliters with 13,000/microliters platelets. Bone marrow puncture revealed that NCC stood at 14,000 with 50.0% blasts. The surface characters of the blasts were CD13+, CD33+, and HLA-DR+, and blood culture tests were positive. Coagulation tests revealed DIC. Based on the foregoing results, hypoplastic leukemia was diagnosed accompanied by sepsis and DIC, and was placed on the concomitant administration of a combination of low dose Ara-C and M-CSF. After 14 days of Ara-C administration and 26 days of M-CSF, her clinical symptoms improved, with the peripheral blood showing a WBC of 2,800/microliters and platelet count of 111,000/microliters. The percentage of myeloblasts decreased to 7.0%. After the administration of Ara-C was suspended for 2 weeks, another course of low dose Ara-C plus M-CSF administration was carried out and the patient achieved full remission. M-CSF stimulates not only the production of monocytes but increases the number of neutrophils and platelets through monocytes. It is also expected that tumoricidal activity may be realized by the activation of monocytes. In this patients, the concomitant administration of M-CSF and low dose Ara-C was remarkably effective in treating hypoplastic leukemia with severe complication. This result suggests that M-CSF will be useful for the treatment of leukemia.