Objective: Erectile dysfunction(ED)is a common problem in the elderly,and the prevalence for cardiovascular(CV)risk factors in this group is relatively high.Recently,there is increasing tendency of ED in young men under the age of 40.These young patients were more likely to have some kind of psychiatric problems instead of organic diseases;however,the CV risk factors may still exist.The aim of this study is to compare the prevalence of CV risk factors between the young male and the elderly with ED.Methods: From June 2013 to May 2015,patients presented to our out-patient clinic with chief complaint of ED were prospectively enrolled.The IIEF-5 questionnaire and common risk factors of CV disease including BMI,diabetes mellitus(DM),dyslipidemia,and smoking were collected.Patients were sub-divided into young age group(age <40)and old age group(age >40).Unpaired t-test,Chisquare test and Fishers exact test were used to evaluate the difference in the prevalence of the CV risk factors between two groups.Results: A total 458 patients were enrolled,and 90(19.7%)of them were in the young age group.The mean IIEF5 score was higher for the young male compared to the elderly(P=0.0037),suggesting that the severity of ED was higher in the elderly.For the prevalence of CV risk factors in the young male,34(37.8%)had overweight or obesity,76(84.4%)had dyslipidemia,and 23(25.6%)were current smoker.There was no DM in the young age group in our patients.The prevalence of overweight/obesity,dyslipidemia,and current smoker between the young and elderly groups were nonsignificantly different.Conclusions: Although young male presented to us with less severity of ED,these patients indeed possessed CV risk factors which may lead to the development of ED.