Thrombotic thrombocytopenic purpura (TTP) is a serious complication following bone marrow transplantation (BMT). Therapeutic plasma exchange does not appear to be effective in its management in contrast to classical TTP. We report the case of a child with TTP 3 years after autologous PBSC transplantation, in whom remission was achieved by administration of cyclosporin A, after failure of plasmapheresis as primary treatment.