Several studies have shown that prolongation of QT interval predicts the risks of all-cause and cardiovascular mortality. Moreover, a close association was reported between prolongations of QT interval and pulse wave velocity (PWV) in general population without preexisting cardiovascular disease. The aim of this study was to evaluate the relationship between QT interval and PWV in patients with type 2 diabetes without preexisting cardiovascular disease. In a cross-sectional study of 251 Japanese patients with type 2 diabetes, we examined the correlation of the heart rate-corrected QT interval duration (QTc) with PWV or other various parameters, including age, duration of diabetes, body mass index, systolic blood pressure, hemoglobin A1c, serum cholesterol, creatinine, uric acid, potassium, severity of diabetic nephropathy or retinopathy and current treatment of diabetes. The QTc correlated positively with PWV (r=0.268, p<0.0001). Multiple regression analysis demonstrated that the QTc was independently correlated with PWV (β=0.155, p=0.0119), after adjustment for known risk factors. According to the receiver operator characteristic analyses (ROC), the area under the ROC curve (AUC) of QTc and the Framingham 10-year coronary heart disease risk score (FRS) for arterial stiffness were 0.69 and 0.64, respectively. The AUC of QTc for arterial stiffness was similar to that of FRS for artificial stiffness (p=0.6532). In conclusion, the QT interval could be a marker of subclinical atherosclerosis in patients with type 2 diabetes.