Coronary heart disease (CHD) mortality rates declined by 22 and 13% for European men and women respectively between 1968 and 1981. Data from two methodologically identical population-based registers indicate that in the period 1974-1981 there was no change in either the event rates or case fatality rates of definite myocardial infarction. In the same period there was a significant 17% decline in the sudden death event rates. These declines have been associated with a decrease in the consumption of dairy products, a reduction in self-reported cigarette smoking habits, improved control of hypertension, and possibly by reductions in serum cholesterol levels and an increase in habitual physical activity in the community. There have also been improvements in the medical management of patients with CHD although this appears to be of secondary importance in contributing to the decline in CHD mortality.