Background: To examine whether the recent flattening of mortality rates for coronary heart disease (CHD) observed among young adults in the UK and the US is also occurring in the Australian population. Methods: Mortality data from 1976 to 2006 were used to calculate overall age-adjusted and age-specific mortality rates for Australian adults aged ≥ 25 years. Joinpoint regression was fitted to estimate the annual change and detect points in time where significant changes in the trends occur. Results: Between 1976 and 2006 age-adjusted CHD mortality rates declined by 73% in men and 70% in women. A steady decline continued in older groups. Beginning in 1991, a slowing of the fall in mortality rates was observed in younger men, and CHD mortality rates were essentially flat in men 25-34 years. Among men aged 35-44, a reduction of the decline in CHD mortality was observed from 1992, and likewise in men aged 45-54 years from 1994. Very similar patterns were observed in women with significant slowdowns starting in 1980, 1988 and 1991 for those aged 25-34 years, 35-44 years and 45-54 years respectively. Conclusions: In Australian men and women aged 25-54 years, the CHD mortality decline has slowed since the early 1990s. The most likely explanations for reduction of the CHD mortality decline are attenuations or reversal of the earlier declines in major traditional risk factors (tobacco smoking, serum cholesterol, blood pressure) and diabetes mellitus. © 2011 Elsevier Ireland Ltd. All rights reserved.