Mortality from coronary heart disease has declined for more than 20 years in several industrialized countries. Partly because of a lack of morbidity data, the reasons for the decline are not satisfactorily established. This community-wide survey of coronary heart disease morbidity and mortality in Malmo, Sweden, showed declining mortality rates beginning in the mid-1970s. Between the 3-year intervals 1975-1977 and 1984-1986, coronary heart disease mortality declined by 17% (2,610/100,000 inhabitants in 1984-1986) in men aged greater-than-or-equal-to 70 years and by 8% (938/100,000 inhabitants in 1984-1986) in men aged 60-69 years, while coronary heart disease mortality in men aged 50-59 years increased by 7% (355/100,000 inhabitants in 1984-1986). In women aged greater-than-or-equal-to 70 years, coronary heart disease mortality decreased by 12% between 1975-1977 and 1984-1986 (1,609/100,000 inhabitants in 1984-1986), while the decrease in women aged 60-69 years was 5% (242/100,000 inhabitants in 1984-1986). The decline in mortality was associated with a decline in both incidence rates and in-hospital case fatality rates for myocardial infarction. The authors suggest that the declining coronary heart disease mortality in Malmo was due partly to prevention of coronary heart disease but that improved medical care for acute and chronic coronary heart disease may also have contributed.