Between 1982 and 1996, 20 patients (10 male, 10 female) with severe aplastic anemia (SAA) with a median age of 25 years (17–37 years), received grafts from an HLA-identical sibling (n = 17), HLA-identical unrelated donor (n= 2) or identical twin (n= 1). The median time from diagnosis to marrow transplantation (BMT) was 15 months (range 1–96 months). More than half of the patients had received more than 10 units of red blood cells or platelet transfusions prior to BMT. Pretransplant immunosuppression consisted of cyclophosphamide (CY) alone (n= 10), CY in combination with total body irradiation (n= 8), and CY and antithymocyte globulin (n= 2). For graft-versus-host disease (GVHD) prophylaxis methotrexate (MTX) alone (n= 9) or MTX with cyclosporin A (n = 10) were given. One patient died on day 18 after marrow grafting due to infection; all other patients had complete and sustained engraftment (95%). Eight patients developed acute GVHD (42%), nine patients chronic GVHD (53%) including four with extensive disease manifestation. One patient experienced a secondary malignancy 11 years after BMT. Eighteen patients followed for a median of 9.45 years (0.42–14.7 years) have sustained hematological reconstitution and are alive and well with a Karnofsky performance score of at least 90%. Thus, excellent long-term survival and low morbidity make allogeneic or syngeneic BMT the treatment of choice for younger patients with severe aplastic anemia.