We performed a retrospective analysis of the medical records of allogeneic bone marrow transplantation (BMT) patients receiving cyclosporine plus an aminoglycoside and autologous BMT patients receiving an aminoglycoside without concurrent cyclosporine in the immediate post-transplant period. Acute nephrotoxicity was not seen in any of the patients. Concomitantly used agents such as acyclovir, vancomycin and amphotericin did not worsen renal function. The present study suggests that aminoglycosides, if carefully monitored, can be safely combined with continuous infusion of cyclosporine without excessive nephrotoxicity.