This article will review the incidence and most common causes of sudden cardiac death (SCD) in healthy young adults, including competitive athletes, as well as members of the general population. SCD is rare but devastating in a young individual. The incidence of SCD in the young ranges from as low as 0.4 per 100,000 patient-years to as high as 13.4 per 100,000 patient-years. SCD occurs in all populations, not only in athletes. Whether SCD is more common in athletes is the cause of continued debate stemming from conflicting data. Hypertrophic cardiomyopathy is the most common underlying cause of SCD in young athletes in most series; however, in nonathletic populations, the underlying causes of SCD are more varied.