The enteroviruses, especially the Coxsackie B viruses, predominate as causative agents in myopericarditis and may be involved in the pathogenesis of dilated cardiomyopathy. Some studies suggest that these and other viruses might be implicated even in atherosclerosis and myocardial infarction. True incidence data of myopericarditis in the population at large are hardly feasible, since the disease is most often mild or subclinical. The long-term prognosis is favorable even in a majority of hospital-treated patients. A recent histopathological study of unselected autopsy cases employing the "Dallas criteria" for a diagnosis shows a myopericarditis incidence of 1.06 per cent. A link between myopericarditis and dilated cardiomyopathy is supported by findings of enteroviral RNA in biopsies and explanted hearts in the latter condition. A partly new panorama of viral heart disease is emerging in heart transplant recipients and AIDS patients.