We assessed the severity of carotid atherosclerosis in 412 men from eastern Finland aged 42, 48, 54 or 60 years at examination with B-mode ultrasonography in 1987 in the Kuopi ischaemic Heart Disease Risk Factor Study (KIHD). Thirty-seven per cent of participants had intimal-medial thickening, 10% had plaques and 2% had stenosis. Age (P less than 0.001), cigarette-years (P less than 0.001), serum LDL cholesterol (P = 0.005), low income (P = 0.020) and low alcohol consumption (P = 0.048) had significant partial associations with the severity of carotid atherosclerosis. A linear regression model including these variables and plasma fibrinogen (NS) and serum HDL-cholesterol (NS) accounted for 33% of the variation in atherosclerosis severity. Our data provide further evidence on the role of smoking and LDL-cholesterol in atherosclerosis.