Hypertension is the most important risk factor for stroke and vascular dementia. Antihypertensive treatment reduces stroke risk by 40%. Most probably, all antihypertensive drugs are equally effective with the exception of alpha blockers. One study showed superiority of an angiotensin (AT) II antagonist versus beta blocker in patients with hypertension and left ventricular hypertrophy. Blood pressure is increased in many patients with acute stroke. In this phase, sudden drops in blood pressure should be avoided. All guidelines concerning antihypertensive treatment in acute stroke are not based on evidence. For secondary prevention, the combination of an angiotensin- converting enzyme (ACE) inhibitor and diuretic reduced strokes by 28% after transient ischemic attack (TIA) or a first stroke. Whether this is a drug-specific effect or due to lowering blood pressure per se is investigated at the moment. Antihypertensive treatment can reduce the incidence of vascular dementia and cognitive impairment.