The present study represents an analysis of 96 patients with severe aplastic anemia (SAA) treated in Seoul National University Hospital, Seoul, Korea between 1990 and 1999. Twenty-two patients were treated by allogeneic bone marrow transplantation (BMT) from HLA identical sibling donors and 74 by immunosuppressive therapy (IS) with antithymocyte globulin (ATG) or antilymphocyte globulin (ALG). There was no statistical difference between the two treatment groups in age, sex, disease duration, and previous transfusion amount. In the BMT group, grade II-IV acute graft versus host disease (GVHD) develeped in 10% and chronic GVHD occurred in 33% of patient. Only one patient died from complication of transplantation (veno-occlusive disease). Of 74 patients who received IS treatment, 45% achieved a complete or partial response. Twenty patients died among IS treatment group. Major causes of death were hemorrhage (40%) and infection (55%). In the BMT group, the 5-yr overall survival (OS) was 95% after a median follow-up of 42 months. In the IS group, the 5-yr OS was 70% after a median follow-up of 49 months (p=0.04). In conclusion, the long-term survival rates of SAA in Koreans receiving BMT or IS were excellent compared with the Western data. Further evaluation on the prognosis of aplastic anemia in Asians should be done.