It has long been established that hypertension is the major risk factor for stroke. Three Italian studies have been reviewed in order to examine different aspects of the problem. In the first study, the role played by the systolic, diastolic and systodiastolic components of hypertension in causing atherosclerotic damage of extracerebral and intracerebral arteries was examined. At the extracranial level, a significant correlation between systolic hypertension and atherosclerotic lesions was evident. The second study evaluated the risk of major stroke, myocardial infarction and death in patients with transient ischemic attacks and reversible ischemic neurologic deficits. Possible prognostic predictors of these events were thoroughly considered: Cumulative survival with the multivariate Kaplan-Meier analysis was significantly lower in hypertensive than in normotensive subjects, particularly for cerebral deaths and for all deaths. The third study was aimed at assessing the risk factors for transient ischemic attacks and stroke in young adults. Again, hypertension emerged as a fundamental risk factor, significantly more frequent in the subgroup of older patients than in the younger subgroup.