Numerous epidemiological studies have shown that the lower the blood pressure the lower the cardiovascular risk. On the other hand, intervention studies with antihypertensive agents in patients with systolic-diastolic or isolated systolic hypertension have shown that the antihypertensive treatment decreases the incidence of cardiovascular events: however it is still undefined which is the better blood pressure goal to reach during antihypertensive therapy. Observational studies and secondary analysis of large randomized trials have shown that treated hypertensive patients with diastolic values below some critical levels have a higher incidence of deaths and cardiovascular events. Studies on different populations evaluated with different protocols have given non-uniform results and many hypothesis have been suggested as causes of low diastolic pressure: 1) excessive antihypertensive treatment, 2) decreased compliance of aorta and large arteries and 3) clinical signs of a concomitant disease. Different studies suggest that diastolic blood pressure values lower than 70-80 mmHg, independently from the responsible physiopathological mechanisms, may rise the risk of cardiovascular events. Therefore, from the clinical point of view, extreme caution in the titration of the antihypertensive therapy for elevated systolic values when the range of diastolic blood pressure is below 70-80 mmHg.