Ample data now exist to dispel the prevailing clinical impression that coronary heart disease (CHD) occurs infrequently in United States Blacks. It is well known that CHD is the leading cause of death among United States Blacks. Among patients with acute myocardial infarction who often present with typical ischemic chest pain, it has been shown that Blacks present more often without chest pain when compared to whites and Hispanics. In addition, more than 25 percent of the myocardial infarction patients have unrecognized infarctions. Morbidity and mortality associated with angina pectoris, cardiovascular disease, and myocardial infarction occurs in United States Blacks at rates which are at least comparable to their white counterparts. Yet, there are limited epidemiological studies designed to identify the determinants of CHD in the Black population.