Cardiovascular disease is the leading cause of death in renal transplant recipients. Arterial wall properties are surrogate markers for arteriosclerosis. Previous investigations have shown that the cardiovascular risk profile is better with tacrolimus compared to cyclosporine. Renal function, blood pressure, and lipid levels improve. The hypothesis is that arterial wall properties will improve after conversion from cyclosporine to tacrolimus. Thirty-four stable renal recipients were converted from cyclosporine microemulsion to tacrolimus without changing concomitant medication. Before and after conversion we performed wall track ultrasounds of the carotid and the brachial arteries; pulse wave velocity (PWV); laboratory investigations; 24-hour ABPM; estimates of renal function; and Framingham risk scores. After conversion the 24-hour ambulatory blood pressure monitoring (ABPM) did not change. Total cholesterol, LDL cholesterol, and triglycerides improved significantly. Renal function (Cockroft) improved. There were no significant changes in arterial wall properties, or in PWV. Framingham comparative risk scores improved only significantly in patients not receiving statins. In conclusion, 3 months after conversion from cyclosporine to tacrolimus total cholesterol, LDL cholesterol, and triglycerides were significantly decreased and renal function significantly improved. Contrary to expectation, ABPM did not change, probably due to prolonged use (>10 years) of cyclosporine. There was also no difference in arterial wall properties.