The anatomic and physiologic changes that occur as a consequence of exercise training have been well described in athletes participating in a variety of different sports.^{1, 5, 10, 25, 41, 43 and 57} It has been established that athletic training is often associated with modest increases in left ventricular chamber size, wall thickness, and mass. Moreover the relative degree of chamber enlargement and hypertrophy appears to be related to the level and intensity of training as well as the type of activity performed (i.e., isometric versus isotonic exercise). It also appears that for given levels and types of training, some individuals show more marked morphologic changes. In this regard, it has been speculated that the cardiac alterations that occur with athletic conditioning may be due, in part, to genetic factors that exist independent of training (i.e., the morphologic changes observed in athletes may be influenced by genetic disposition).^{35, 37 and 43} Related to this issue is the possibility that racial (or biologic) differences in cardiac response to exercise may also exist and may, in part, explain the morphologic variability encountered among athletes. There are few actual data to support racial differences in cardiac response to exercise; however, the concept that cardiac morphology per se may be influenced by race is not without precedent. For example, substantial evidence suggests that racial differences in the cardiac response may occur in systemic hypertension.^{19, 20, 27, 28 and 39} This article reviews the available data that address racial differences in the cardiac response to exercise and to left ventricular pressure overload and evaluates the implications of these findings in the athlete's heart.