Sudden cardiac death (SCD) is the leading cause of fatalities in competitive athletes during sports and exercise. These tragic events often receive intense public attention and stimulate debate regarding the most appropriate prevention strategies. A precise understanding of SCD incidence is needed to guide effective screening programmes and proper emergency preparations at athletic events. However, published estimates of SCD incidence vary widely, and are strongly influenced by the methodology used for case identification (numerator) and calculations of the population at risk (denominator). Studies searching only media reports or catastrophic insurance claims tend to underestimate SCD risk. Few studies with mandatory reporting of SCD are available, leaving significant knowledge gaps in our understanding of SCD in competitive athletes. In general, SCD is more common in males, black athletes, and male basketball players. This chapter reviews the incidence of SCD in athletes and examines differences based on gender, race, sport, and geographic region.