2014 American Heart Association, Inc. Stroke is available at http://stroke.ahajournals.org DOI: 10.1161/STR.0000000000000046 AHA/ASA Guideline Meschia et al Guidelines for the Primary Prevention of Stroke 3755 Stroke changes the lives not only of those who experience a stroke but also of their family and other care- givers. A major stroke is viewed by more than half of those at risk as being worse than death.4 Despite the advent of reperfu- sion therapies for selected patients with acute ischemic stroke, effective prevention remains the best approach for reducing the burden of stroke.5 7 Primary prevention is particularly important because >76% of strokes are first events.1 Fortunately, there are enormous opportunities for preventing stroke. An international case-control study of 6000 individuals found that 10 potentially modifiable risk factors explained 90% of the risk of stroke.8 As detailed in the sections that follow, stroke-prone individuals can readily be identified and targeted for effective interventions. This guideline summarizes the evidence on established and emerging stroke risk factors and represents an update of the last American Heart Association (AHA) statement on this topic, published in 2011.9 Targets for stroke prevention have been reordered to align with the AHA s public health campaign for ideal cardiovascular health known as Life s Simple 7.10 As with the earlier document, the guideline addresses prevention of both hemorrhagic and ischemic stroke. 