We report the results of allogeneic bone marrow transplantation (BMT) in a 15-month-old boy with severe combined immunodeficiency (SCID) complicated by disseminated Bacillus Calmette-Guerin (BCG) infection. Slow immunological recovery after BMT is considered to be associated with prolonged BCG infection. After one booster dose of allogeneic peripheral blood stem cell transplantation (PBSCT), there was still little improvement in immune reconstitution. The patient finally expired because of failure to achieve a functioning immune system after BMT and septic shock.