We measured the intima-media thickness of the common carotid artery (CCA) and of its bifurcation (BIF) in 20 borderline hypertensives (age 24 ± 4 years) and in 20 normotensive subjects (age 23 ± 6 years), as a control group. Both carotid axes have been scanned from different views on a transversal and longitudinal section. Carotid diameter and thickness were measured in the longitudinal section. CCA parameters were assessed 20 mm caudally to the flow divider. In borderline patients blood pressure (147.8 ± 10.5/90.7 ± 6.6 mm Hg) and left ventricular mass index (102.5 ± 15.3 g/m<sup>2</sup>) were significantly higher than in normotensive subjects (blood pressure 120.5 ± 11.5/78.0 ± 5.4 mm Hg; left ventricular mass 90.5 ± 14.3 g/m<sup>2</sup>, p < 0.01 and p < 0.05 respectively). The intima-media thickness of both the CCA and BIF was significantly higher in borderline hypertensives than in normotensives(CCA 0.6 ± 0.08 vs. 0.4 ± 0.05 mm, p < 0.01; BIF 0.7 ± 0.08 vs. 0.5 ± 0.08, p < 0.01). In the whole population there was a statistically significant correlation between the carotid wall thickness and the left ventricular mass. In conclusion our data show that ultrasonography provides direct evidence that in young borderline hypertensives the increased left ventricular mass is associated with vascular hypertrophy.