A wide spectrum of cardiovascular abnormalities may cause sudden death in young athletes, and even minor lesions may be life-threatening by jeopardizing the electrical order of the heart during effort. The culprit diseases are clinically covert and difficult to diagnose or suspect. Early identification during systematic preparticipation screening might reduce the risk and incidence of sudden death. In the time interval 1979-1996, 49 young athletes died suddenly in the Veneto Region. The prevalence of sudden death was calculated as 0.75/100,000/year among young nonathletes and 1.6/100,000/year among young athletes (p < 0.01). Among athletes, arrhythmogenic right ventricular cardiomyopathy was the leading cause, followed by atherosclerotic coronary artery disease and congenital coronary anomalies. Hypertrophic cardiomyopathy has been a very uncommon cause of fatal events, due to the identification and disqualification of affected subjects at the preparticipation screening. Only arrhythmogenic right ventricular cardiomyopathy and congenital anomalies of coronary arteries occurred more frequently in athletes than in nonathletes, as to indicate that these diseases are particularly prone to cardiac arrest during effort. The rarity of prodroma in patients affected by coronary artery disease, both acquired and congenital, particularly the absence of chest pain, stresses the difficulty in suspecting these lesions. On the opposite, most of athletes with arrhythmogenic right ventricular cardiomyopathy had something that might have alerted, either in terms of family history or electrical disorders. Our data are strongly in favor of an effective role of the Italian protocol for preparticipation screening in preventing sudden death in young athletes affected by hypertrophic cardiomyopathy. With increased awareness of diagnostic criteria, also athletes with concealed arrhythmogenic right ventricular cardiomyopathy will be identified in the future and sudden death possibly prevented.