Viral infections of the pericardium occur frequently. Unfortunately, the viruses responsible for the infection are rarely isolated or even identified. The clinical manifestations are those of fluid in the pericardium and usually an associated friction rub. There is no specific treatment for a viral agent, but supportive care is important and valuable. The diagnostic and therapeutic principles in the clinical care of patients with viral pericarditis are discussed. Viral pericarditis never occurs without associated subepicardial myocarditis and often occurs in association with diffuse myocarditis. For this reason the disease may be better termed viral myopericarditis.