Objectives: We conducted a study to evaluate the impact of obesity on erectile function in men with erectile dysfunction. Methods: Three hundred and twenty-five consecutive patients with erectile dysfunction were evaluated. We classified the men into 2 groups according to body weight: < 120% of the ideal body weight, and ≥ 120%. We compared several erectile capacities and the findings of penile duplex ultrasonography. Results: There was a statistically significant decrease in the quality of residual erectile function in patients with obesity (penile rigidity grade 1.32 versus 1.62 in the nonobese patients). Obese patients also have an increased prevalence of vascular risk factors based on a review of the medical records and vascular impairment by duplex ultrasound study (43 and 62% in the obese patients versus 30 and 42% in the nonobese patients, respectively, p < 0.05). However, when we focused only on the patients without any vascular risk factors, no significant difference between the 2 groups was noted in the quality of residual erectile function and also the prevalence of penile vascular impairments (p > 0.05). Conclusions: These data demonstrate that obesity in itself does not seem to be an underlying factor, but does impose a risk to vasculogenic impotence by developing chronic vascular disease.