The benefits of long-term cyclosporin (CyA) therapy are not yet established and must be weighed against its toxicity. We studied cardiovascular risk factors in 25 patients who received a kidney transplant between 1985 and 1989 and in whom CyA was discontinued. The protocol for discontinuing CyA involved starting azathioprine (Aza) and then weaning CyA over 6 weeks without changing the prednisone dose. Parameters collected from the patients' charts 3 months before (pre) and 3 months after conversion (post) and at the most current follow-up (cur) included serum creatinine, cholesterol, blood pressure, and anti-hypertensive medication. The severity of the hypertension was graded, based on a hypertension index reflecting the nature and dose of the anti-hypertensive medication. Of the 25 patients in whom CyA was discontinued, 2 experienced a rejection episode during conversion and were switched back to CyA; 1 patient had a rejection episode after conversion but remained on Aza. Converted patients demonstrated improved renal function (1/Cr pre 0.69 +/- 0.20, post 0.84 +/- 0.23, P < 0.05), lower serum cholesterol levels (pre 6.8 +/- 1.0, post 5.8 +/- 1.2, P < 0.05), lower mean arterial pressure (pre 111 +/- 14, post 102 +/- 8, P < 0.05) and a lower hypertension index (pre 2.45 +/- 2.77, cur 1.62 +/- 1.70, P < 0.05). Although conversion may carry some risk of acute rejection, it improves graft function and the cardiovascular risk profile significantly.