Subjects with heart diseases at risk of sudden death may be free from symptoms and be able to perform high-level sports activities. Preparticipation screening helps to detect these diseases, reducing the risk of sudden death in athletes. Fortunately, sudden death in athletes is a rare event (1-2/100 000 in subjects aged <35 years). As a consequence, it is not clear whether extensive preparticipation screening is cost-effective. In Italy pre-participation screening is mandatory for both agonistic and nonagonistic sports, whereas in the United States it is not requested. In addition, many US authors suggest that compulsory medicine visits are in conflict with the freedom of any people to self-determine its own destiny. In the presence of heart disease, international guidelines exist that provide recommendations for sports eligibility. Although all of them are similar, US guidelines are more permissive. Guidelines are not laws. However, in case of legal disputes, they are taken into account and, hence, it is a good rule to know and follow them.