Coronary heart disease (CHD) has been the greatest single cause of mortality in Australia over the past 30 years. For most age and sex groups CHD mortality rates peaked in 1965–67. Since that time, rates have decreased by nearly 40% and are currently the lowest for 30 years. CHD mortality rates are highest in the eastern areas of Australia, among those who were born in Australia, and among lower socio-economic groups. Changes in CHD mortality have been accompanied by changes in life-style (particularly recent decreases in the prevalence of cigarette smoking, large reductions in tar content of cigarettes and a large change in preference for margarine over butter) and changes in treatment (especially in the control of hypertension and surgical interventions). Concurrent studies of the incidence and case fatality rates in two population centres (Perth and Newcastle) coupled with periodic surveys of changes in treatment and population risk factor levels are being undertaken over a 10-year period to try to understand the current and future trends in CHD mortality.