The objective of this cross-sectional controlled study was to evaluate the intima-media thickness (IMT) of the common carotid artery (cIMT) and superficial femoral artery (fIMT), as well as the elastic properties of the common carotid artery, in children with essential arterial hypertension. The study included 49 children with newly detected essential hypertension [mean age 14.5 (range 6-20) years] and 61 healthy normotensive children [mean age 13.5 (range 6-20) years]. The cIMT and fIMT were evaluated by ultrasonography. The elastic properties of the carotid artery were calculated from actual blood pressure values, arterial dimensions, and carotid wall thickness. Hypertensive children had greater values of both cIMT (0.45+/-0.05 mm) ( P=0.0001) and fIMT (0.37+/-0.05 mm) ( P=0.005) than controls (0.41+/-0.04 and 0.33+/-0.06 mm, respectively). The internal systolic and diastolic diameters of the common carotid artery were also significantly greater in hypertensive patients. The distensibility and elasticity of the common carotid artery were significantly decreased in hypertensive patients, while arterial compliance was significantly greater than in controls. cIMT and fIMT correlated with systolic and pulse pressure values, body mass index (BMI), homocysteine, low high-density lipoprotein, and apolipoprotein AI. After subdividing the control group and patients according to BMI below or above the 95th percentile for age and sex, there were differences only between normal-weight normotensive children and the two groups of hypertensive children. The stepwise regression analysis showed that the predictive factor for cIMT was pulse pressure and for fIMT body mass and homocysteine. Hence, in newly diagnosed children with essential hypertension, functional and anatomical changes in elastic and muscular arteries are observed. Pulse pressure and biochemical risk factors for cardiovascular damage were predictors of vessel wall injury, even if it remained within the normal range. BMI is an important factor influencing IMT values.