Background : Erectile dysfunction occurs in 15% to 50% of men, and increases with age. International Index of Erectile Function (IIEF-5) questionnaire is a tool for screening and assessing the response to erectile dysfunction treatment. With USG, especially CDUS of the penis, we can evaluate penile vascular condition, by measuring PSV and EDV, we can determine the type of penile vascular disturbance whether it comes from arteries or veins or combination of both. Objective : This study aims to determine relationship between degree of erectile dysfunction according to IIEF-5 and color doppler ultrasound image of the penis evaluated in the flaccid phase. Methods : This study is a prospective observational study conducted on 30 samples with varying degrees of erectile dysfunction. USG examination was performed in flaccid phase with peak systolic velocity (PSV), cavernous artery diameter, end-diastolic velocity (EDV), and resistive index (RI) parameters. Data normality test done by a regression test with dummy variables. Results : We found 30 patients with various degrees of erectile dysfunction, mild (36%), mild (27%), moderate (27%), severe (10%). There?s strong relationship between degree of erectile dysfunction and PSV value (72.32%). The average RI value of study was 0.77. There?s no correlation between degree of erectile dysfunction and cavernous artery diameter. Conclusion : There?s a strong relationship between degree of erectile dysfunction with PSV and RI value. There?s no significant relationship between degree of erectile dysfunction and the cavernous artery diameter.