Hypertrophic cardiomyopathy (HCM) is the main cause of sudden unexpected death in the young and especially in young athletes with an incidence up to 2.3 per 100,000 athletes and year. Risk stratification models including patient history (syncope, familial risk of sudden death) and findings in noninvasive tests (nonsustained ventricular tachycardia, abnormal blood pressure response during exercise, maximum left ventricular wall thickness > or = 30 mm) have been developed in order to estimate the risk of individual patients. Echocardiographic parameters are helpful in distinguishing HCM from athlete's heart. Definitive diagnosis of HCM implicates disqualification from competitive sports resulting in a significant reduction of sudden cardiac death due to HCM during sports competition. This positive development should lead to a widespread preparticipation screening of athletes including historical, clinical, and electrocardiographic examination. At least in borderline findings and symptomatic athletes, an additional echocardiogram should be performed in order to minimize or better exclude the risk of sudden cardiac death.