Current guidelines established in the USA and Europe for coronary artery bypass graft (CABG) suggest that patients 65 and 70 years of age, or with certain atherosclerotic-risk factors, should be screened preoperatively for extracranial carotid artery stenosis (CAS) to assess their risk of perioperative stoke. We sought factors that should be taken into consideration when treating Chinese CABG patients using CABG guidelines based on an analysis of CAS in a large cohort of Chinese CABG patients.We analyzed data for 1558 Chinese CABG patients who were screened preoperatively for CAS using duplex ultrasonography at a single institution. We defined significant and severe CAS as 50% and 70% stenosis, respectively, in one or more common or internal carotid arteries. We investigated the prevalence of CAS, the incidence of perioperative stroke, and the risk factors for CAS in the CABG cohort.The prevalence of CAS in the CABG cohort was 21.2%. Multivariate stepwise logistic regression analysis showed that an age 50 years and a history of smoking (odds ratios=8.36 and 1.83, respectively) were independent risk factors for CAS (P<0.05 for both). The incidence of perioperative stroke among CABG patients with significant or severe CAS was significantly higher (2.4% and 2.9%, respectively) than in CABG patients with <50% stenosis (0.5%; P=0.004 and 0.029, respectively).Chinese CABG patients with a history of smoking or 50 years of age should undergo preoperative screening for CAS to assess their risk of perioperative stroke.