In 1993 the NIH (National Institute of Health) Consensus Conference on Impotence defined erectile dysfunction as the permanent incompetence to start or maintain an erection enough to enable satisfactory sexual intercourse.Erectile dysfunction (ED) is a frequent disorder that affects negatively quality of life of males suffering it. Its prevalence varies between different countries, cultures and races. The first population studies published date from early 90`s and still keep their validity. All of them show the influence of age on prevalence of ED, as well as its close relationship with cardiovascular diseases. Depending on the definition used and study design prevalence varies from 10 to 52%, mainly in men between 40-70 years, with an incidence in western countries between 25-30 new cases per 1000 inhabitants year.