Since 1976 there has been a leveling off or slowdown in the rate of decline in coronary heart disease (CHD) mortality. The age-adjusted absolute annual rate of decline in CHD mortality rates during 1968-75 (delta rate/100,000 population/year) was virtually identical for White males (-7.54), Black males (-7.85), and Black females (-7.20), and somewhat lower for White females (-4.25). During 1976-85, however, the secular trends diverged considerably. Age-adjusted rates continued to decline at the same annual rate for White males, while the decline was approximately half as steep for the other three race-sex groups. During 1976-85 there was also a leveling off in the average annual per cent change in age-adjusted CHD mortality for Black males and females and White females when compared to 1968-75, while there was no change for White males. As a result, more than 40,000 White and Black females and Black males died of CHD in 1985 than would have died if CHD rates would have continued to decline at the 1968-75 trends. All comparisons were based on a reclassification of cause-of-death codes to maximize comparability between the 8th and 9th Revisions of the International Classification of Disease. These results suggest that the factors which have led to the continued decline in coronary heart disease may not have influenced all the demographic groups in this country equally over the last decade.