Aplastic anemia is a rare disease, which is characterized by pancytopenia and hypocellular bone marrow without infiltration of abnormal cells or fibrosis. The incidence in Asia is higher than in the West and new cases are diagnosed at a rate of 5.1 per million pediatric populations per year in Korea. The pathophysiology is understood roughly by defective hematopoiesis, impaired bone marrow microenvironment and immune mechanism. Treatments are performed on basis of pathogenesis and selected depending on the severity. Immunosuppressive therapy with antilymphocyte or antithymocyte globulin and cyclosporine is effective in the majority of patients but has some problems including relapse or clonal evolution. Recently, there have been clinical trials of immunosuppression with hematopoietic growth factors or other drugs. Allogeneic hematopoietic stem cell transplantation (HSCT) is curative in children with severe aplastic anemia. The overall survival in HSCT from HLA-identical sibling is higher than alternative donor, including HLA matched unrelated donor or cord blood. We have to consider quality of life after HSCT because of high survival rate. However, chronic graft versus host disease and graft failure are important factors that affect the quality of life and overall survival. We need further investigation to make new regimens aimed at overcoming these risk factors and perform clinical trials.