The Working Conference on Coronary Heart Disease in Black Populations should define an agenda for research to determine (1) the degree to which the persistent socioeconomic differences between U.S. blacks and whites are important environmental determinants of differing risk factor distributions and (2) whether these differences have a differential impact on the natural history of coronary disease in these groups. In addition, research should be directed toward the resolution of existing controversies and to the testing of hypotheses suggested by earlier work. In the definition of this agenda, attention must be paid to the methodologic problems identified in this article. The resolution of the controversies and the testing of hypotheses suggested by ethnic comparisons are of intrinsic scientific importance for ischemic heart disease research and is likely to yield insights of value in diminishing the heart disease burden in all segments of the population.