Arterial hypertension is the most important risk factor for stroke. Many interventional trials have unambiguously proven the benefit of antihypertensive therapy in both primary and secondary prevention for all age categories. No recommendation for any single antihypertensive substance for the primary prevention of stroke exists. Achieving the therapeutic goal (normotension) is the crucial factor. In most patients, multiple combinations of antihypertensive drugs are required to do this. For high-risk patients and in secondary prevention, substances inhibiting the renin-angiotensin-system, especially combined with calcium antagonists and indapamid, may be advantageous, while beta-blockers appear to be less well suited. In patients suffering from left-ventricular hypertrophy or atrial fibrillation, sartanes are the best-documented drug class. As TIA or stroke will often disturb the normal circadian rhythm of blood pressure and eliminate the usual night-time drop, monitoring of the therapeutic results must include ambulatory 24h measurements. The interrelation between vascular dementia and hypertension is by now also considered proven. An early start of antihypertensive treatment can prevent the development of dementia and impaired cognitive function.