After allogenic transplantations, a dramatic increase in the development of arteriosclerotic plaques can be observed, which might be due to metabolic alterations, changes in the transplant organ, or the immunosuppression regimen. Many studies have demonstrated beneficial effects of tacrolimus compared with cyclosporine with regard to these conditions. These results have suggested that conversion to tacrolimus from cyclosporine is advantageous. Our study investigated whether patients with deteriorating renal function profit from this conversion. Thirty renal transplant patients were studied retrospectively, using data recorded from 3 years before to 3 years after conversion from cyclosporine to tacrolimus. While renal function (GFR) deteriorated progressively under cyclosporine, it stabilized and even improved under tacrolimus (creatinine: DeltaCyc = +1.4 mg/d; DeltaTac = -0.7 mg/dL; GFR: DeltaCyc = -35 mL/min; DeltaTac = 14 mL/min). In addition, uric acid levels (7.0 mg/dL vs 6.4 mg/dL, P < .05) and cholesterol levels (258 mg/dL vs 225 mg/dL, P < .05) were both significantly lower under tacrolimus. Conversion from cyclosporine to tacrolimus is recommended for kidney transplant patients in whom there has been a progressive fall in renal function. It leads to stabilization or even improvement of transplant function and a reduction in cardiovascular risk factors.