Neutropenia is a major dose-limiting side effect of cancer chemotherapy. The therapeutic effect of HM 10411 was examined on neutropenia caused by anticancer agents. Neutropenia in normal ICR mice was induced by a single combined intraperitoneal injection of 130 mg/kg of cyclophosphamide (CPA). 4.5 mg/kg of doxorubicin (DXR). and 1 mg/kg of vincristine (VCR) on day O. Neutropenia in tumor-bearing mice was made by a single intraperitoneal injection of 200 mg/kg of cyclophosphamide (CPA) into BALB/c mice bearing Colon 26 adenocarcinoma at 7 day after tumor implantation. HM 10411 or filgrastim (100 $mu extrm{g}$/kg/day) was subcutaneously administered for 5 consecutive days starting 1 day after injection of anticancer agents in order to stimulate neutrophil production. Injection of HM 10411 accelerated the recovery from these anticancer drug-induced neutropenia. In normal and tumor-bearing mice. neutrophil production efficacy of HM 10411 was similar than that of filgrastim. These results suggest that HM 10411 could be useful in the clinical treatment for neutropenia induced by anticancer agents.