BACKGROUND AND PURPOSE: The presence of carotid plaque reflects overall atherosclerotic burden and may predict coronary artery disease events. We examined the association among carotid atherosclerosis, history of atherothrombotic events, and risk of coronary events. METHODS: Among 45 227 patients in the Reduction of Atherothrombosis for Continued Health (REACH) Registry with 4-year follow-up, 23 364 patients with information on carotid atherosclerosis at baseline were analyzed. The primary outcome was the composite of first occurrence of cardiovascular death, myocardial infarction, or coronary hospitalization. RESULTS: The carotid atherosclerosis was present in 46% of patients (n=10 725) and was associated with increasing conventional cardiovascular risk factors and extent of symptomatic vascular disease. During 4-year follow-up, 4304 patients experienced >/=1 coronary event. After adjustment for cardiovascular risk factors and geographic region, the risk of coronary events increased by 22% (95% confidence interval [CI], 14%-30%) in patients with versus without carotid atherosclerosis. The relative increase was 18% (95% CI, -7%-51%) in patients enrolled with multiple risk factors only, 25% (95% CI,16%-35%) in patients with coronary artery disease, 46% (95% CI,28%-65%) in patients with cerebrovascular disease, and 37% (95% CI,17%-60%) in patients with peripheral artery disease. Carotid atherosclerosis was associated with increased risk, even among patients with previous myocardial infarction but no known stroke (P=0.001) or among patients with previous stroke but no known myocardial infarction (P<0.001). CONCLUSIONS: Carotid atherosclerosis was an independent predictor of coronary events across all types of symptomatic vascular disease and had an incremental effect on risk regardless of risk factors or location of vessel disease.