Background Carotid intima-media thickness (CIMT) is associated with cardiovascular mortality in patients with cardiovascular risks. We sought to evaluate the impact of CIMT on long-term prognosis in patient with coronary atherosclerosis. Methods Study population consisted of 1764 consecutive patients (mean 64.7짹10.1 years old, 956 male) who underwent coronary angiography and carotid artery scanning with high-resolution ultrasound. Study subjects were divided to quartile group according to mean CIMT: 1st quartile 0.65짹0.06mm, 2nd quartile 0.77짹0.03mm, 3rd quartile 0.87짹0.03mm, 4th quartile 1.12짹0.21mm. Results A total of 1296 patients (73.5%) were clinically followed-up for mean 31.4짹23.4 months. . 4th quartile group had higher incidence of diabetes, hypertension and dyslipidemia than the 1st and 2nd quartile group, respectively. Kaplan-Meier analysis, death and myocardial infarction (MI) were higher in 4th quartile group than 1st and 2nd quartile (Log rank 4.04, p=0.044 and Log rank 6.85, p=0.009), respectively. In multiple logistic regression analysis, MI (HR 2.75, 95% CI 1.54-4.92, p=0.001), 4th quartile CMIT (HR 1.84, 95% CI 1.07-3.17, p=0.029) and dyslipidemia (HR 1.93, 95% CI 1.10-3.37, p=0.021) were independent risk factor of death and MI. Conclusion An increased CIMT is associated with poor long-term prognosis in patient with coronary atherosclerosis. This study suggests that increased CIMT can be another marker for death or MI in patients with coronary artery disease.