OBJECTIVE: To describe the prospective relationship between social networks and nonfatal stroke events in a sample of women with suspected myocardial ischemia. Social networks are an independent predictor of all-cause and cardiovascular mortality, but their relationship with stroke events in at-risk populations is largely unknown. METHOD: A total of 629 women (mean age = 59.6 ± 11.6 years) were evaluated at baseline for cardiovascular disease risk factors as part of a protocol including coronary angiography; the subjects were followed over a median 5.9 years to track the incidence of cardiovascular events including stroke. Participants also completed the Social Network Index (SNI), measuring the presence/absence of 12 types of common social relationships. RESULTS: Stroke events occurred among 5.1% of the sample over follow-up. More isolated women were older and less educated, with higher rates of smoking and hypertension, and increased use of cardiovascular medications. Women with smaller social networks were also more likely to show elevations (scores of ≥10) on the Beck Depression Inventory (54% versus 41%, respectively; p = .003). Relative to women with higher SNI scores, Cox regression results indicated that more isolated women experienced strokes at greater than twice the rate of those with more social relationships after adjusting for covariates (hazard ratio = 2.7; 95% Confidence Interval = 1.1-6.7). CONCLUSIONS: Smaller social networks are a robust predictor of stroke in at-risk women, and the magnitude of the association rivals that of conventional risk factors. Copyright © 2008 by American Psychosomatic Society.