Although myocarditis has been known for almost two centuries, data in regard to its incidence have varied widely. Autopsy studies have reported an incidence of 3.5% to as high as 10%. The main reason for such diversity of data appears to be the lack of unanimity as to what constitutes myocarditis. Recently, definitions of myocarditis have been proposed and precise criteria for the morphologic recognition of myocarditis have been published. In this study an analysis of 12,747 consecutive autopsies performed from 1975 to 1984 at Malmö (Sweden) General Hospital was carried out. Applying the newly proposed histologic criteria, the diagnosis of myocarditis was made in 136 cases, which constitute 1.06% of the autopsy population studied. This rate of myocarditis incidence at postmortem is lower by far than rates previously published.