The SYNTAX score (SS) and SS II, which include additional clinical parameters, are widely used today for deciding revascularization following coronary angiography. We investigated the association between the presence and severity of carotid artery disease (CrAD) using the SS and SS II in 287 patients who underwent coronary artery bypass grafting. We based this investigation on the known association between coronary artery disease and CrAD. A significant association was observed between the groups with and without CrAD in terms of SS II values (28.4 ± 9.6 vs 21.4 ± 7.7, respectively; < .001). A significant difference was also observed when stenosis was classified according to severity as <50%, 50% to 70%, and >70% ( < .001). The results indicated a positive correlation between the presence and severity of CrAD as SS II increased ( = 0.187, = .005). According to the results of multivariate logistic regression analysis, the SS II was an independent predictor of CrAD.