Over the last 25 years, a sustained and marked decline in death rates from coronary heart disease (CHD) has occurred for all major segments of the U.S. population. Recently, however, the decline has proceeded less rapidly in blacks than in whites, and in women than men. These trends have focused further attention on possible heterogeneity in the risk factor patterns among the demographic sub-groups. Previous studies of CHD risk factors in blacks and whites using the First National Health and Examination Survey Epidemiologic Follow-up Study (NHEFS-I, 11-year follow-up), including this group's own work, demonstrate its potential strengths, while at the same time foundering on the problem of low statistical power. With the extension of the follow-up of NHANES-I cohort (1971-1974) to 1987 (14 years) and the completion of 14-year follow-up for NHANES II cohort (1976-1980), a strong rationale exists to undertake a "pooling project." The resulting data set would provide optimal characterization of CHD risk at the national level.