A 69-year-old woman with pure red cell aplasia and granular lymphocytic leukemia was reported. Because her granular lymphocyte count was in the normal range at the time of admission, we diagnosed the patient as primary pure red cell aplasia (PRCA). The granular lymphocyte count increased slowly, and we find monoclonal T cell receptor rearrangement, the case was diagnosed as granular lymphocytic leukemia accompanied with PRCA. Although single administration of cyclosporin or cyclophosphamide induced severe side effects obtained combined administration of low doses of these agents obtained good Hb increase. This case was granular lymphocytic leukemia with normal granular lymphocytic count at the time of diagnosis, the tumor cell suppressed BFU-E colony formation, and combined administration of low dose CPM and CyA yielded good effects.