Purpose: A normal coronary angiogram and slow coronary flow in patients with angina has been explained as abnormally high small-vessel resistance and increased microvascular tone. Also, there was reported that the patient with slow coronary flow was related with impaired endothelial function. The aim of this study was to evaluate the arterial stiffness by measuring the aortic pulse wave velocity (PWV) in patients with slow coronary flow. Methods: We enrolled the 20 patients (male 7, 57.8짹11.8 yrs) with normal coronary flow (NCF) and 16 (male 6, 56.8짹13.0 yrs) with slow coronary flow. We excluded the patient with diabetes and positive myocardial stress test. We defined slow coronary flow as TIMI 2 coronary flow by two experts. We measured the aortic pulse wave velocity, argumentation index (AI), left ventricular ejection fraction (LVEF), left ventricular mass index, serum C-reactive protein, and plasma homocysteine. Results: In patients with TIMI 2 coronary flow, the PWV was significantly increased compared than it of NCF (p<0.05) and the LVEF was also significantly lower (p<0.05). However, other parameters such as AI, serum CRP and plasma homocysteine were not different between two groups. Conclusions: These findings suggested that arterial stiffness was increased in patients with TIMI 2 coronary flow.