Myocarditis and pericarditis are rare but important causes of pediatric chest pain. The diagnositic criteria, clinical course, causes, and treatment of myocarditis is reviewed. There is particular attention to the relationship of myocarditis with dilated cardiomyopathy. Supportive therapy remains the standard of care for pump dysfunction. The identification and treatment of pericarditis with associated large pericardial effusion can be lifesaving. This article reviews the important clinical features that might lead the clinician to diagnose either myocarditis or pericarditis and thus separate the few patients with either of these conditions from the legions of children with noncardiac chest pain.