Bone marrow transplantation with a small to medium-sized single hospital team is feasible. It leads to results similar to those observed at large centers and with the same major risk factors: age, stage of the disease at the time of transplant, degree of histocompatibility, graft-versus-host disease prevention method, and selection. A single small to medium-sized center cannot conduct prospective randomized studies but it can pioneer new concepts. Bone marrow transplantation today offers a good choice for patients suffering from otherwise lethal bone marrow diseases. These include severe aplastic anemia, acute leukemias, chronic myeloid and chronic lymphoid leukemia, myelodysplastic syndrome, and congenital disorders. Changes in outcome are due to innovative steps, such as the introduction of CsA for GvHD prevention. In addition they are certainly influenced by unrecognized changes in the patient selection process.