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. The traditional definition of ischemic stroke as a clinical event is used in most instances out of necessity because of the design of most stroke prevention studies; however, where permitted by the evidence, the Writing Group has adopted the updated tissue-based definition of isch- emic stroke as infarction of central nervous system tissue.11 Differences in stroke risk among men and women are well recognized, and certain risk factors are specific to women s health (eg, oral contraceptives [OCs] and hormone replace- ment therapy). To increase awareness of these important issues and to provide sufficient coverage of the topic, theAHA has issued a guideline on the prevention of stroke in women.11a Key recommendations are summarized in the current docu- ment but not reiterated in full. Readers are encouraged to review the new guideline. The committee chair nominated Writing Group members on the basis of their previous work in relevant topic areas. The AHA Stroke Council s Scientific Statement Oversight Committee and the AHA s Manuscript Oversight Committee approved all Writing Group members. In consultation with 2 research librarians, we developed individual search strategies for each topic section and for each database to identify poten- tially relevant studies from the PubMed, Ovid MEDLINE, Ovid Cochrane Database of Systematic Reviews, and Ovid Central Register of Controlled Trials databases. The Internet Stroke Center/Clinical Trials Registry (http://www.strokecenter.org/ trials/) and National Guideline Clearinghouse (http://guideline. 