Immunosuppression (IS) therapy with antilymphocyte globulin (ALG) is currently the treatment of choice for patients with aplastic anemia who do not have histocompatible sibling donors or who are not candidates for allogeneic bone marrow transplantation. Thirty-eight patients with aplastic anemia who received ALG-based therapy at a single institute in Taiwan were analyzed, and 28 were followed up for more than 6 months. Four patients (10.5%) had a complete response, and 11 (28.9%) had a partial response. The overall response rate was 39.4%. The significant prognostic factor that affected the response to IS therapy was a positive test result for antibodies to the hepatitis C virus. The rate of early mortality (death within 90 days after initiation of ALG-based therapy) was 15.8%, and most deaths were secondary to infection. Factors influencing the risk of early mortality were old age, hypotension, and bacteremia. In conclusion, ALG-based IS therapy was effective for aplastic anemia in Chinese patients. The role of hepatitis C associated with aplastic anemia and its relationship to IS need to be clarified by further investigations.