We aimed to correlate the predisposing demographic and clinical factors for erectile dysfunction (ED) in young men and treatment response in these men with data from older men. The patients were divided into two groups: <40 years (group I, n = 58) and >= 40 years (group II, n = 73). ED was evaluated with the International Index of Erectile Function-5 (IIEF-5) questionnaire, and Beck's Depression Inventory (BDI) questionnaire was used to evaluate mood status. The number of patients with morning rigidity and normal libido was higher in group I (70.7% vs. 16.4%, p = .039 and 72% vs. 37%, p = .047). The increase in scores other than IIEF-Orgasmic Function and Sexual Desire domain scores after treatment was higher in the first group (p = .029, p = .035 and p < .001 respectively). In multivariate analysis, the factors predicting the low IIEF-Erectile Function domain score in young men were testosterone level and BDI score (p = .026 and p = .034). Although psychogenic factors contribute significantly to the aetiology of ED, hormone profile is more preserved in young men than in older men.