Introduction. Stroke, together with ischemic cardiopathy, may be considered to be a vascular epidemic in the developed world, where it is a major social and health problem. In Spain it is the commonest cause of death in women and the second commonest in men. Development and conclusions. In this article we review the risk factors which cannot be modified (age, sex, inheritance, race, geography and climate) and the well-established risk factors which can be mortified (arterial hypertension. cardiopathies with a high risk of embolization, markers for atherosclerosis, diabetes mellitus and transient ischemic accidents). A wine understanding of these risk factors permits the identification of persons with a high risk of having an ischemic stroke. Therefore preventive and therapeutic measures to reduce individual risk from strokes (and their recurrence) and hence reduce morbimortality from this, can be designed.