Cyclosporine (CsA) has substantially improved patient and graft survival rates in solid organ transplantation. In clinical studies, sirolimus has been shown to be as effective as CsA to maintain survival of renal and cardiac allografts without causing nephrotoxicity. Herein we describe a patient with biopsy-proven CsA-associated nephrotoxicity and refractory renal allograft rejection who was converted from steroids, CsA, and azathioprine to steroids, sirolimus (RAPA), and low-dose mycophenolate mofetil (MMF). The follow-up period was 60 months. We observed substantial improvement, even normalization in renal function. Our patient did not give consent to repeat biopsy after conversion. We also observed a beneficial effect of CsA withdrawal on blood pressure control. The spectrum of adverse events induced by sirolimus seemed to be mild relative to the potency of the immunosuppressive effect. The excellent response to combined RAPA and MMF in this patient was probably due to "concerted actions" of these agents on both B- and T-cell functions. The combination enhanced therapeutic efficacy while minimizing the toxicity of individual drugs used in the regimen. These findings suggest that sirolimus, when used as a base therapy in combination with low-dose MMF in a renal allograft recipient, may be an alternative to CsA-based therapy, providing potent immunosuppression of a renal allograft. Sirolimus administration facilitated steroids dose reduction.