Although SCD is relatively uncommon, its psychosocial impact is devastating. This article has reviewed the potential causes of SCD in infants, children, and adolescents. Many patients who die from SCD have identifiable cardiac disease and are known to have been at risk; however, the existence of other cardiac abnormalities, such as hypertrophic cardiomyopathy or long QT syndrome, may not be known, and SCD may be the first symptom. The authors' contention is that many of the patients in this latter group (e.g., patients who have hypertrophic cardiomyopathy or LQLTS but who have no symptoms) can be screened with a careful, accurate, and detailed history, including family history and review of systems, and physical examination. Any patient with a positive family history, positive review of systems, or positive physical examination should receive further in-depth evaluation, such as an ECG and echocardiogram. These studies permit the detection of most, if not all, of the entities potentially associated with SCD in the pediatric population.