We investigated the effects of long-term therapy with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in a 69-year-old man with severe aplastic anemia (SAA). The patient was too old to receive a bone marrow transplantation, and high-dose methylprednisolone and antilymphocyte globulin were ineffective. We administered rhG-CSF in combination with metenolone acetate. Trilineage blood cell components were recovered 6 months later. These findings suggest that long-term G-CSF therapy may be beneficial in patients with SAA who are not candidates for bone marrow transplantation.