Although aortic stiffness plays an important role in patients with coronary artery disease (CAD), the influence of aortic stiffness on left ventricular systolic function has not yet been fully evaluated. In the present study, we measured brachial-ankle pulse wave velocity (baPWV), which is a new index of aortic stiffness, in patients with CAD (CAD group, n = 170, 67 ± 9 years old) and without CAD (non-CAD group, n = 81, 63 ± 8 years old), and evaluated the relationship between baPWV and left ventricular systolic function in patients with CAD. baPWV in the CAD group was significantly higher than that in the non-CAD group (1,794 ± 350 vs. 1,469 ± 292 cm/s, p < 0.05), although both systolic and diastolic blood pressure were comparable between the two groups. In the CAD group, the baPWV was higher in patients with three-vessel disease than that in patients with one-vessel disease (1,885 ± 542 vs. 1,720 ± 373 cm/s, p < 0.05). In the CAD group, multivariate analysis demonstrated that baPWV and pulse pressure independently correlated with left ventricular ejection fraction (LVEF). In conclusion, in patients with CAD, baPWV, which is a simple marker of aortic stiffness, increases with CAD severity and correlates with left ventricular systolic function independent of CAD severity.