Objective: To examine the association between social relationships measured by the Social Network Scale and coronary artery disease (CAD) risk and mortality among a sample of women with suspected CAD. Methods: Five hundred three women (mean age, 59 years) with suspected CAD warranting clinical investigation completed a diagnostic protocol including psychosocial testing, CAD risk factor assessment, and quantitative coronary angiography. Patients were subsequently followed for a mean of 2.3 years to track all-cause mortality. Results: Women reporting higher social network scores showed a consistent pattern of reduced coronary artery disease risk, including lower blood glucose levels (r = -0.11; p = .03), lower smoking rates (odds ratio [OR] = 0.81; 95% confidence interval [CI] = 0.71-0.93; p = .002), lower waist-hip ratios (r = -0.18; p < .01), and lower rates of hypertension (OR = 0.90; 95% CI = 0.81-0.99; p = .04) and diabetes (OR = 0.83; 95% CI = 0.73-0.94; p = .004). Based on quantitative angiogram findings, high social network scorers also had less severe CAD (mean angiogram stenosis value, 40.8 vs. 27.2 for low and high scoring social network groups, respectively; p < .001). Finally, mortality rates over follow-up showed a dose-response pattern in relation to quartile scorers on the Social Network Index, with low scorers showing more than twice the death rate of high scorers (relative risk = 2.4; p = .03). Conclusions: Among a cohort of women with suspected CAD, smaller social circles were associated with increased CAD risk factors and mortality, an effect that appeared to be explained largely by income level. The findings extend previous studies of social network effects on health by highlighting risk among women with suspected CAD, and suggest mechanisms for further study.