Objective We hypothesize that generalized vascular dysfunction may be the underlying cause in patients with erectile dysfunction (ED) without atherosclerosis and its major risk factors. Methods In all, 30 outpatients with ED and 25 healthy volunteers as a control group were enrolled for this study. Aortic stiffness was calculated from data obtained by echocardiographic examination, which was performed using commercially available equipment with a 2.5- to 3.5-MHz transducer. Endothelium-dependent flow-mediated dilation (FMD) of the brachial artery was assessed using a high-resolution ultrasound system with a 10-MHz linear-array vascular transducer. Shear stress and nitroglycerin was used as a stimulus for assessing endothelium-dependent FMD and nonendothelium-dependent dilation of the brachial artery. Results FMD was significantly decreased in the ED group compared with control group (4.1 ± 3.1% vs 9.7 ± 3.5%, P < .001). Nonendothelium-dependent dilation was statistically insignificant in patients with ED compared with control subjects (13 ± 3.9% vs 15.4 ± 3.8%, P = .55). The relationship between ED and FMD was significant ( r = −0.66, P < .001), whereas no relationship was found between ED and nonendothelium-dependent dilation ( r = −0.23, P > .05). Aortic strain (3.7 ± 2.7% vs 9.5 ± 3.2%, P < .001) and distensibility (1.5 ± 1.0 vs 4.7 ± 2.9 cm 2.dyne −1.10 −3, P < .001) were found significantly lower in the ED group than in the control group. The relationship between ED and aortic stiffness was also significant (for aortic strain; r = −0.62, P < .001 and for aortic distensibility; r = −0.60, P < .001). Conclusion Aortic and brachial artery functions are impaired in men with ED without cardiovascular disease or its major risk factors, indicating a more generalized vascular disease.