Twenty-four patients have received bone marrow transplantation for severe aplastic anaemia at the Westminster Hospitals since 1974. Twelve patients are long term survivors. Infectious complications in association with graft rejection, graft versus host disease or prolonged neutropenia were the major cause of death. In the last 18 months the introduction of more effective conditioning regimes and Cyclosporin A as graft versus host disease prophylaxis has improved the survival rate to 85%. One patient has required regrafting for late graft failure without evidence of graft rejection.