Bone marrow transplantation (BMT) in patient affected by severe aplastic anemia (SAA), is successful in 70-80% of cases, when performed with HLA identical brother or syngeneic twin as donors, and in 11-45% of cases when performed from aploidentical-identical related or HLA identical unrelated donor. The different conditioning regimens (Cy alone or in combination with TBI) have shown similar results in the long term outcomes. Cyclosporin-A is very effective in avoiding rejection and controlling GVHD.