Competitive sports activity is associated with an increased risk of sudden cardiovascular death (SCD) in adolescents and young adults with clinically silent cardiovascular disorders. While in middle-aged/senior athletes atherosclerotic coronary artery disease accounts for the vast majority of SCDs, in young athletes the spectrum of substrates is wider and includes inherited (cardiomyopathies) and congenital (anomalous origin of coronary arteries) structural heart diseases. Inherited ion channel diseases have been implicated in SCDs occurring with an apparently normal heart at autopsy. Screening including the ECG allows identification of athletes affected by heart muscle diseases at a pre-symptomatic stage and may lead to reduction of the risk of SCD during sports. The use of modern criteria for interpretation of the ECG in the athlete offers the potential to improve the screening accuracy by reducing the number of false positives. Screening with exercise testing middle aged/senior athletes engaged in leisure sports activity is likely to be effective in patients with significant coronary risk factors, while it is not useful in low-risk subgroups. The availability of automated external defibrillator on the athletic field provides a "back-up" preventive strategy for unpredictable arrhythmic cardiac arrest, mostly occurring in patients with coronary artery diseases.