Stroke is a personal,familial,and social disaster.It is the third cause of death worldwide,the first cause of acquired disability,the second cause of dementia,and its cost is astronomic.The burden of stroke is likely to increase given the aging of the population and the growing incidence of many vascular risk factors.Prevention of stroke includes—as for all other diseases—a "mass approach" aiming at decreasing the risk at the society level and an individual approach,aiming at reducing the risk in a given subject.The mass approach is primarily based on the identification and treatment of vascular risk factors and,if possible,in the implementation of protective factors.These measures are the basis of primary prevention but most of them have now been shown to be also effective in secondary prevention.The individual approach combines a vascular risk factor modification and various treatments addressing the specific subtypes of stroke,such as antiplatelet drugs for the prevention of cerebral infarction in large and small artery diseases of the brain,carotid endarterectomy or stenting for tight carotid artery stenosis,and oral anticoagulants for the prevention of cardiac emboli.There is a growing awareness of the huge evidence-to-practice gap that exists in stroke prevention largely due to socio-economic factors.Recent approaches include low cost intervention packages to reduce blood pressure and cheap "polypills" combining in a single tablet aspirin and several drugs to lower blood pressure and cholesterol.Polypill intake should however not lead to abandon the healthy life-style measures which remain the mainstay of stroke prevention.