Objectives: This study sought to determine the prevalence of hypertrophic cardiomyopathy (HCM) in elite athletes. Background: Hypertrophic cardiomyopathy is considered to be the most common cause of exercise-related sudden death in young athletes. The prevalence of HCM in elite athletes has never been reported but has important implications with regard to pre-participation screening for the disorder. Methods: Between 1996 and 2006, 3,500 asymptomatic elite athletes (75% male) with a mean age of 20.5 ± 5.8 years (range 14 to 35 years) underwent 12-lead electrocardiography and 2-dimensional echocardiography. None had a known family history of HCM. Results: Of the 3,500 athletes, 53 (1.5%) had left ventricular hypertrophy (mean 13.6 ± 0.9, range 13 to 16), and of these 50 had a dilated left ventricular cavity with normal diastolic function to indicate physiological left ventricular hypertrophy. Three (0.08%) athletes with left ventricular hypertrophy had a nondilated left ventricular cavity and associated deep T-wave inversion that could have been consistent with HCM. However, none of the 3 athletes had any other phenotypic features of HCM on further noninvasive testing and none had first-degree relatives with features of HCM. One of the 3 athletes agreed to detrain for 12 weeks, which showed resolution of electrocardiography and echocardiographic changes confirming physiologic left ventricular hypertrophy. Conclusions: The prevalence of HCM in highly trained athletes is extremely rare. Structural and functional changes associated with HCM naturally select out most individuals from competitive sports. Screening athletes with echocardiography is not cost effective. However, electrocardiography is useful in selecting out those individuals who may have pathological left ventricular hypertrophy for subsequent echocardiography.