Clinical and basic science studies provide strong indirect evidence that smoking may affect penile erection. The objective of this retrospective research was to investigate the role of smoking for erectile dysfunction (ED) in order to obtain some insight into the prevention of ED. We reviewed the data from 860 male patients aged between 18 and 44 visited during the period January 1999 to December 2002. The patients were divided into three groups: smokers, never smokers and former smokers. All patients were submitted of medical history, such as, IIEF 5 Questionnaire, physical examination, serum levels of glucose, cholesterol, prolactin and free testosterone. Our data were compared with ISTAT (Italian Institute of Statistics) and data on the Italian population of smokers. We have stratified the data by age and area of residence. The 860 patients, mean age 32.4 y old (range 18-44), are distributed into three groups: smokers 460 (53.5%), never smokers 320 (37.2%) and former smokers 80 (9.3%). Current smokers in our series are 460 (53.5%) in comparison to 34.7% of male current smokers in Italy, in the same range (18-44). Out of 860, 337 are patients who smoked more than 20 cigarettes per/day (39.2%) and these data are extremely interesting; while comparing the same aged men through ISTAT, it is found that only 4% are heavy smokers. On analysing the incidence of heavy smoking in middle-aged patients affected by ED with the whole Italian population by means of ISTAT, taking into account males with the same age range and area of residence, it was shown that the data of our population (sample) compared all Italian middle-aged patients are 39.2 vs 4%; this explains the need for education within a comprehensive smoking cessation programme, and should be reserved especially for young smokers, in order to be aware and informed of the effect of tobacco on erectile function.