Left ventricular (LV) echocardiography and ambulatory monitoring of blood pressure (BP) were performed in 50 normal 20-year-old subjects previously followed longitudinally for 4 years with annual measurements of basal BP (BBP). The relationship of basal, casual and mean 24-h non-invasive ambulatory BP (ABP) with echo findings, blood chemistries and body fatness was evaluated. Subjects with mean BBP on the 4 years above the 85th percentile showed significantly higher blood levels of urea and glucose and of body fat than subjects below this BP level. Left ventricular echo measurements did not differ in the two groups. Left ventricular diameters and volumes were not correlated with basal, casual or ambulatory BP. Interventricular septum (IVS), LV posterior wall (LVPW) and LV mass were correlated with ambulatory systolic but not with basal or casual BP. A significant increase of wall thickness and LV mass was associated with a mean 24-h ambulatory systolic BP (ASBP) above 129 mmHg. It is concluded that random BP and ABP tend to identify hypertensive subjects with different features.