The recent developments in the study of myocarditis and dilated cardiomyopathy are reviewed here, with the primary emphasis on the issue of myocarditis as a precursor to dilated cardiomyopathy. Advances in immunologic approaches have expanded our knowledge of the course of myocarditis, experimentally as well as clinically. Although further investigations are necessary to prove the direct link between acute myocarditis and some cases of dilated cardiomyopathy, clinical trials of immunosuppressive agents, virus-specific vaccine, and antiviral agents such as ribavirin and interferon appear warranted, with the hope of potential benefits in the treatment of myocarditis and, therefore, in some forms of dilated cardiomyopathy.