PURPOSE: The purpose of this study is to compare treatment response and survival according to treatment modalities, such as allogeneic bone marrow transplantation (BMT), combined immunosuppression and supportive care, and according to etiologies in children with severe aplastic anemia. METHODS: Thirty-four patients who had severe aplastic anemia received either BMT, combined immunosuppression, or androgen treatment at Chonnam University Hospital from Jan. 1990 to Mar. 1998. The clinical characteristics and response according to treatment modalities or etiologies were studied retrospectively. RESULTS: 1) Patients in Group 1 received combined immunosuppression of ALG/ATG+methylprednisolone+/-cyclosporin (N=18); Group 2, BMT (N=11); Group 3, supportive treatment of oxymetholone+prednisolone+transfusion (N=5). Clinical characteristics were not different among three groups. 2) In Group 1, the response rate was 50% with complete response (CR) in 4 (22.2%) and partial response (PR) in 5 (27.8%). CR was attained in 91% (10/11) of Group 2 patients, while all 5 in Group 3 were died. Relapse was found in 1 out of 9 (11.1%) in Group 1. Three of 10 in Group 2 who had initial response experienced late graft failure. The Kaplan-Meier 4-year-survival in each group was 75.5%, 81.8% and 20%, respectively (P = 0.019). 3) Among 5 patients were Fanconi's anemia, two survived who underwent HLA- matched sibling transplants. Three patients with secondary aplastic anemia, including posthepatitis (N=2) and post-rubella responded to either BMT or immune suppression. Idiopathic cases (N=26) showed response rate of 43.8% to immunosuppression [CR, 3/16; PR 4/16], 85.7% to BMT, and 0% to supportive care. 4) The relative risk of death was 0.26 (P = 0.052) in Group 1, and 0.15 (P = 0.03) in Group 2 in comparison with Group 3. CONCLUSION: The study showed that BMT and combined immunosuppression resulted in better response and survival than supportive care in the management of childhood severe aplastic anemia. Although BMT seemed to be better than immunosuppression, effective measure to reduce late graft failure and graft versus host disease should be pursued.