Socioeconomic structure refers to aspects of communities -- their industries, physical resources, occupational and income distributions -- that create the conditions for change in health-related exposures, behaviors, and availability of quality medical care. Preliminary studies suggest growing inequalities in ischemic heart disease mortality in communities at different levels of socioeconomic structure that probably reflect both differences in timing of onset of decline and rate of decline of mortality. Despite the beginning of a national decline of ischemic heart disease mortality for white men in the middle 1960's, some communities only began the decline some years later, at which time the national decline accelerated. Late declining communities were more likely to be nonmetropolitan and in the South. Further analyses showed that the onset of decline was strongly related to measures of socioeconomic structure, and that income-related characteristics could account for much of the previously observed metropolitan differential. Another study showed that the decline of ischemic heart disease in both white men and women has been greater in county groups with occupational structures characterized by higher levels of white collar employment. The trend toward greater relative geographic inequality of mortality appears to be stronger for ischemic heart disease than for stroke, all cardiovascular disease or all-cause mortality. Prevention strategies should take account of these processes not only to achieve a more equitable distribution of health but to target populations with the greatest excess risk available for reduction.