The sudden unexpected death of an athlete is a disturbing and tragic event. Sudden cardiac death in the young athlete is caused primarily by cardiomyopathies and nonatherosclerotic coronary artery abnormalities; in the mature athlete, the most prevalent cause of sudden cardiac death is atherosclerotic coronary disease. The job of the emergency physician is to resuscitate those who succumb to ventricular dysrhythmias during exercise and to screen patients for potential risk of sudden cardiac death when they present with warning symptoms such as syncope.