This article reviews the theories regarding the causes of lymphocytic myocarditis, including viral and immunologic (cellular versus humoral) causes. Also covered is the relationship of dilated cardiomyopathy to myocarditis, the familial predilection for dilated cardiomyopathy in some cases, shortcomings of the various modalities for diagnosing lymphocytic myocarditis, and the occurrence of lymphocytic myocarditis in association with systemic illnesses. Lastly, treatment options for myocarditis are explored.