The aim of our study was to evaluate the behaviour of venous pressure in patients with systodiastolic arterial hypertension as compared with elderly patients suffering from isolated systolic hypertension and with healthy controls. We studied 125 subjects subdivided into three groups: Group A, formed by 32 patients, aged between 43 and 73 years, with a mean age of 63.25+/-12.3 years, suffering from mild to moderate systodiastolic essential arterial hypertension (SDH); Group B, including 50 patients, aged between 58 and 83 years, with a mean age of 71.53+/-8.43 years, with isolated systolic hypertension (ISH); Group C, formed by 43 subjects, aged between 13 and 72 years, with a mean age of 42.91+/-17.84 years, as a healthy control group (CS). Patients observed a period of pharmacological washout for at least 15 days before the beginning of the study. All underwent a diet with a normal sodium intake. Brachial arterial pressure was always measured at 9 a.m., by using a mercury sphygmomanometer. The venous pressure was measured at the fold of the elbow on the basilic vein, using a Doppler ultrasound instrument. The SBP was similar in patients with SDH (Group A) and in those with ISH (Group B); in both groups SBP was significantly higher than in CS (Group C) (p<0.001). The DBP was significantly higher especially in patients of group A, but also in patients of group B, in comparison with subjects of group C and in patients with SDH in comparison with those with ISH. Venous pressure (VP) proved to be significantly higher in both groups of hypertensives in comparison with CS and in SDH in comparison with ISH (14.76+/-1.90 in Group A vs 12.53+/-2.39 in group B vs 8.75+/-2.02 mmHg in group C, p<0.0001). Considering ten subjects, matched for sex and age in each group, we observed again that VP values in SDH were >ISH>CS (14.3+/-2.9 vs 9.7-/+1.8 in SDH vs CS, 13.5-/+2.1 vs 10.7+/-1.9 in ISH vs CS, 15.6+/-2.2 vs 11.6+/-2.6 mm Hg in SDH vs ISH, p<0.001). In all three considered groups a significant correlation between the values of SBP and DBP with VP (p<0.001) was observed. In conclusion, data from our study show that hypertension is a disease in which both the arterial and the venous vascular beds are involved with increased pressure in both circulatory beds.