Erectile dysfunction is defined as the inability to achieve and maintain an erection sufficient for satisfactory sexual activity. Research shows that over 50% of men between the ages of 40 and 70 suffer from ED, but the exact number is difficult to estimate, given that many men rarely seek medical help about the problem. ED can be etiologically classified into psychogenic, organic, and mixed ED. Organic ED includes vasculogenic, neurogenic, endocrinological and medicamentous etiologies. ED causes a decline in the quality of life of the patient and his partner. Stress and depression often accompany ED, so over time almost all organic dysfunctions usually become mixed. The most common risk factors for ED are hypertension, diabetes mellitus, smoking, dyslipidemia, obesity, physical inactivity and stress. Basic procedures for diagnosing ED include a thorough medical history, physical examination, hormonal and biochemical analyses, and assessment of the patient's psychological profile. Some patients will require further testing. The first-line therapy for ED includes lifestyle changes, pharmacotherapy with oral PDE5 inhibitors and the use of vacuum-assisted erection devices. In case that the first-line therapy isn't effective, intracavernous injections of alprostadil or intraurethral alprostadil suppositories are used as second-line therapy. The third-line therapy includes surgical methods.