One year after heart transplantation, serum total cholesterol had increased by 24% in 103 recipients on prednisolon, cyclosporin A, and azathioprin immuno-suppression, and was above 5.2 mmol/l in 84 of them. Incremental small dose lovastatin treatment up to 20 mg per day safely reduced total cholesterol by 19% and LDL-cholesterol by 24% in 14 patients with serum cholesterol above 7.5 mmol/l. Serum concentration of lovastatin did not increase further after three weeks treatment with 20 mg. It is concluded that hypercholesterolaemia in heart recipients treated with cyclosporin A can be treated safely with small dose lovastatin. Drug therapy should be individualized and conducted by physicians experienced in transplantation medicine.