Aim: To evaluate whether the response to sildenafil administration in patients with arterial erectile dysfunction (ED) was related to their peak systolic velocity (PSV), peripheral atherosclerosis, cardiovascular risk factors (RF) and/or comorbidities at low cardiovascular risk. Methods: We enrolled 97 patients with 1-2 RF and comorbidities, com-bined with arterial ED alone (group A, n=27), ED plus atherosclerofic carotid artery (group B, n=23), ED plus lower limb artery abnormalities (group C, n=25), and ED plus carotid and lower limb artery abnormalities (group D, n=22). Sildenafil efficacy (100 mg twice a week for 12 weeks) was also examined in patients with ≥ 3 RF, peripheral atherosclerosis and no cardiovascular comorbidities (group E, n=20). Results: Median PSV was 24.1, 21.0, 19.3,14.5 and 17.5 cm/s in groups A, B, C, D and E, respectively. Sildenafil response was higher in group A patients (77.8%),intermediate in groups B and C (65.2% and 56%) and lowest in groups D (45.4%) and E (50%), and the response in latter two groups was significantly lower than in the other three groups. In addition, sildenafil response was nega-tively influenced by:≥ 3 RF, peripheral atherosclerosis and no systemic comorhidity, or presence of 1-2 RF associ-ated with extended atherosclerosis and comorbidities. The number of comorbidities was positively related to athero-sclerosis localization or extension (25, 35, 38 and 47 in groups A, B, C and D, respectively). Conclusion: Low sildenafil efficacy in patients with arterial ED was associated with extended atherosclerosis. These patients should undergo extensive ultrasonography and a full cardiovascular examination.