A randomized controlled study of patients with multiple myeloma was performed to evaluate the efficacy and safety of recombinant human granulocyte colony-stimulating factor (rhG-CSF:KW-2228) in treating neutropenia induced by chemotherapy, and its influence on the dose intensity of, and response rate to, chemotherapy. As a rule, 3 courses of chemotherapy at intervals of 4 weeks were administered both to the untreated and KW-2228-treated groups. Among 98 eligible patients evaluated for neutrophil recovery, a markedly reduced duration of neutropenia was observed during each course in the KW-2228 treated group. No significant difference distinguished the two groups in terms of incidence or duration of infection. However, febrile neutropenia appeared only in the untreated group. There was no significant difference in terms of response rate or dose intensity. However, only patients in the untreated group withdrew from the study due to protracted neutropenia. These results demonstrated that KW-2228 is effective and safe, and has a significant effect on the acceleration of neutrophil recovery in patients with neutropenia induced by chemotherapy for multiple myeloma, and is useful for the completion of chemotherapy regimens.