Since the most recent update to guidelines for the management of erectile dysfunction (ED) by practitioners, epidemiological studies have confirmed the main figures emerging from the large international studies done in the late 1990s. Other data have emerged, and we now have a better understanding of the epidemiological profile of ED. Its prevalence for all age groups appears to be between 12.9% (11.5–14.3) in southern Europe and 20.6% (18.8–22.4) in English-speaking countries. More recent longitudinal studies show that incidence is between 32% and 80%, depending on patient age group at enrolment. Recent advances in our understanding of ED have been brought to us by analytical epidemiology. ED primarily affects older people, for whom (according to some studies) it can even be a marker of increased mortality risk. It is less well tolerated by older people than it used to be; for this population group, maintaining their sex lives is an important aspect of quality of life. It is also very poorly tolerated, with significant effects on mood and relationships, by vulnerable patient populations (those with diabetes or hypertension, patients with cardiovascular disease, etc.). As an endothelial disease, ED is very often a sign of organ and/or vascular complications, and of worsening of the underlying disease. The high prevalence of ED in men with depression or lower urinary tract problems has also been confirmed in recent studies. Particular attention is currently being paid to young people; an association of high ED prevalence with substance and alcohol abuse in young men has been found in several studies.