Severe aplastic anemia can be treated with either bone marrow transplantation (BMT) or immunosuppressive therapy (IST). A retrospective review of patients with severe aplastic anemia treated with both of these modalities was conducted. Fifteen BMT and 16 IST patients were available for analysis, and follow-up of 22 and 15 years was available for the BMT and IST groups, respectively. Median survival was limited to 4.3 months in BMT patients vs. 135.2 months in IST patients, despite the older median age of the latter (22 vs. 55 years). Actuarial survival at 1 and 5 years was 87% and 78% for the IST patients and 40% and 33% for the BMT patients. Hematologic response rates, as defined by achievement of transfusion independence, were similar for the two groups. Long-term responses and survival are possible with antithymocyte globulin/cyclosporin A.