In pediatric kidney transplant recipients, tacrolimus has been proposed either for primary immunosuppression or as a rescue agent for refractory acute rejection, chronic rejection, and cyclosporine toxicity. This paper describes our experience with tacrolimus conversion from cyclosporine-based therapy in six selected cases: four due to refractory acute rejections unresponsive to conventional therapy, one to chronic graft rejection, and one to cyclosporine-related hypertrichosis. A "simple-switch" conversion was used without any overlap, starting with a dose of 0.2 mg/kg per day. The time to conversion varied from 10 to 730 days after the transplant. In the patients with acute rejection, the median time to reversal after tacrolimus conversion was 12 days. The symptoms of the patient with cyclosporine toxicity completely resolved without any loss of allograft function. The patient with chronic rejection maintained stable renal function for more than 1 year after conversion. A new onset of post-transplant diabetes mellitus and dose-related nephrotoxicity were recorded as adverse events. In conclusion, our experience suggests that tacrolimus can play an important role in the salvage treatment of pediatric kidney transplantations with deteriorating graft function due to acute rejection refractory to standard therapy. Tacrolimus conversion also provides excellent results in the presence of cyclosporine toxicity.