We retrospectively analyzed data on T- and B-cell reconstitution and infectious complications in 58 children undergoing ABMT, in order to evaluate post-transplant supportive care measures used during the study period. Normalization of T-cell number and lymphocyte proliferative responses to phytohemagglutinin (PHA) and alloantigen (MLC) occurred in two-thirds of children by 6 months post transplant. Normal IgM levels developed in 75% of children by 6 months post transplant. A total of 34 children (59%) developed 39 episodes of infection between neutrophil engraftment and 1 year post transplant. The most common infections included bacteremia, varicella-zoster virus infection and pneumonia, which represented 46, 23 and 9% of infections, respectively. All patients with bacteremia had a central venous catheter in place at the time of infection. Most infections (77%) developed by 6 months post transplant. In this small patient cohort, time to normalization of tests of T- and B-cell function was not significantly different between patients with and without infection. Earlier removal of an indwelling central venous catheter may decrease the risk of bacteremia post transplant. Post-transplant supportive care measures may be discontinued at 6 months post ABMT in most children, as the risk of infection decreases after that time.