From 1974 to 1984, decreases in the mortality of ischaemic heart disease of 11% for men 30 to 69 years of age and 16% for women in the same age-group were observed. From the Copenhagen City Heart Study, a population study of 20,000 men and women, a significant decrease in per cent of smokers, a significant decrease in P-cholesterol, a significant increase in per cent of joggers, but no change in systolic blood pressure were demonstrated, between 1976-1978 and 1981-1983. The decrease in mortality of ischaemic heart disease, may be due to reduction in risk-factor levels, and to advanced medical and surgical treatment.