This review of the current epidemiological literature on erectile dysfunction (ED) suggests that approximately 5-20% of men have moderate-to-severe ED. Different definitions of ED, age distributions and concomitant medical conditions, as well as methodological differences, may explain much of the variance in reported prevalence rates. Various chronic disorders are associated with elevated rates of ED including depression, diabetes, and cardiovascular and neurological diseases. Such disorders are more common in the elderly, which may partially explain the elevated prevalence of ED in men over 60 y of age. Currently, up to 70% of men with ED are not treated. However, so many men experience considerable distress from their condition, that the increasing awareness of ED as well as the availability of noninvasive treatments may result in a greater proportion of patients seeking treatment, and eventually regaining satisfaction with their sex life.