Purpose: Smoking is associated with consistent and widespread changes in small arteries and arterioles independent of the atherosclerosis process. Both passive and active smoking is associated with an acute deterioration in the elastic properties of the aorta. We evaluated the acute effects of passive smoking in non-smoker on arterial stiffness by measuring carotid-radial pulse wave velocity (PWV). Methods: All participants were grouped into non-smokers (n=13, mean age 23.6짹4.0 yrs) or smoker controls (n=26, mean age 23.62.2 yrs, smoking history 3.9짹2.8 pack/yr). All subjects were young male persons without cardiovascular risk factors. They abstained from caffein, ethanol and active and passive smoking in 12 hours before the study. One smoker smoked two cigarettes (nicotine 1.3mg) within 10 min in a closed room, and another smoker and non-smoker were in the same room for passive smoking. We measured peripheral blood pressure, and carotid-radial PWV at basline, 15, 30, 60, 90 and 120 min. Results: Systolic blood pressure was significantly higher in active smoking of smoker group than in passive smoking of non-smoker group at 15 min. Active or passive smoking in all subjects significantly increased PWV as compared with baseline levels. However, there was no difference on the change between peak and baseline PWV among the groups. Conclusions: Passive smoking of non-smoker would have an acute detrimental effect on arterial stiffness as that of active smoking.