To determine the feasibility of detecting cardiovascular disease in a large group of young competitive athletes, a prospective screening evaluation of intercollegiate student athletes was undertaken at the University of Maryland. Initial clinical screening (including personal and family history, physical examination and 12 lead electrocardiogram) was performed in 501 athletes. Ninety of these subjects had positive findings on one or more of the three studies and agreed to further cardiologic evaluation. The vast majority (75 [84%] of 90) had no definitive evidence of cardiovascular disease, although 1 athlete had mild systemic hypertension and 14 (15%) had echocardiographic evidence of relatively mild mitral valve prolapse that had not been previously suspected. In three athletes with relatively mild ventricular septal hypertrophy (14 to 15 mm), it was not possible to discern with absolute certainty whether the wall thickening was a manifestation of hypertrophic cardiomyopathy or secondary to athletic conditioning ("athlete heart"). Therefore, this screening protocol identified no athletes with definite evidence of hypertrophic cardiomyopathy, Marfan's syndrome or other cardiovascular diseases that convey a significant potential risk for sudden death or disease progression during athletic activity. This failure to identify such diseases could have been due to a lack of sensitivity of the screening tests or to the low frequency with which these diseases occur in youthful healthy athletes. A systematic preparticipation screening program (such as the present one) does not appear to be an efficient means of detecting clinically important cardiovascular disease in young athletes.