The pathological diagnosis of myocarditis rests on well-described histopathological criteria. Appreciation for the disease-specific sensitivity of the endomyocardial biopsy, as well as the phenotypical and functional nature of inflammatory infiltrates, will enhance the clinical utility of the biopsy technique. New information regarding the role of enteroviruses in immunological sensitization and the study of enteroviruses in murine models and human patients are fostering new perspectives and routes of investigation of appropriate therapeutic interventions for myocarditis.