Sirolimus is a new immunosuppressive agent. This study aimed to evaluate the efficiency and safety of sirolimus in patients after renal transplantation. We reviewed the clinical follow-up of patients transplanted at our center using sirolimus protocols. From Feb 2001 to Dec 2003, 40 renal transplant patients were treated with sirolimus in different combinations and settings with mean follow-up of 14 months. 20 patients (group A) were treated with Sirolimus-cyclosporine-steroid regimen and cyclosporine withdrawal at 3 months post-transplant, 10 patients (group B) were treated with Sirolimus - low dose tacrolimus-steroid regimen (with or without induction) and tacrolimus withdrawal at 6 months post-transplant and 10 patients (group C) with progressive chronic allograft nephropathy converted to Sirolimus immunosuppression (mean time after transplantation: 8.2 months). The acute rejections were in 5% of patients (1/20) and 10% of patients (1/10) and renal function at 12 months: mean serum creatinine was 1,3mg/dl and 1mg/dl for group A and group B, respectively. Sirolimus conversion due to progressive chronic allograft nephropathy (group C) improved serum creatinine from 1.74 +/- 0.32 to 1.42 +/- 0.18 mg/dL. Conclusion: these new strategies in immunosuppression in kidney transplantation are associated with good results in graft and patient survival in year 1, and with better renal function. Therefore, we can hope for better long-term results in transplantation, with a significant increase in the graft and patient survival.