Cardiovascular disease is the leading cause of mortality in older persons in the United States. Nearly two-thirds of all deaths in men and women 65 years of age or older are due to some manifestation of cardiovascular disease. Further, cardiovascular disease is a major cause of disability in the elderly. Although there is relatively extensive epidemiologic data on risk factors for cardiovascular disease in younger individuals, particularly younger men, in 1986 when the study was initiated, relatively little information existed on the prevalence and antecedents of cardiovascular disease in men and women over 65 years of age. Further, the data that did exist tended to be contradictory. From a public health perspective, it was important to identify risk factors for cardiovascular disease in older individuals for several reasons. The numbers and proportion of elderly persons in the U.S. were growing, and would continue to grow well into the next century. This segment of our society, which comprised 12 percent of the population in 1986, accounted for one third of our health care costs. Older Americans will continue to make significant demands on the health care system in the coming decades. The identification of risk factors for this major public health problem (e.g., cardiovascular disease) may lead to interventions which would improve the health of older Americans and thus benefit the entire society.