To estimate the relationship between structural changes in the heart and in the carotid arteries in hypertensives and to analyze the correlations between these structural changes and cardiovascular risk factors. We studied 76 subjects (39 men and 27 women, mean age 45+/-7 years) with mild-to-moderate untreated and uncomplicated hypertension. All of the subjects underwent ambulatory blood pressure monitoring, M-mode echocardiography for evaluation of their left ventricular mass and B-mode high-resolution ultrasonography to determine their carotid arterial wall thickness. The mean intimal plus medial thickness of the common carotid artery was found to be related significantly and independently to the left ventricular mass indexed by the body surface area. In multivariate analysis, age and the high-density lipoprotein cholesterol level were related strongly to the intimal plus medial thickness, whereas the clinic systolic blood pressure, average night-time systolic blood pressure and glycemia were the most important determinants of the left ventricular mass index. Logistic regression analysis suggested that the thickness of the posterior left ventricular wall was a stronger predictor of the carotid intima-medial thickness than were age and the high-density lipoprotein cholesterol level. The carotid wall thickness and left ventricular mass of hypertensives are related independently; nevertheless the main determinants of structural cardiac and vascular changes are probably different.