Clinical features of 11 patients of acute Coxsackie B viral myocarditis diagnosed by neutralizing antibody titers were reported. All patients had a flu-like symptom and 8 patients had fever. Initial cardiac manifestations were congestive heart failure in 9 patients, and syncopal attack in 4 patients. Electrocardiographic abnormalities frequently observed were non-specific ST-T changes, low voltage, and intraventricular conduction, disturbances including 4 patients of complete A-V block due to trifascicular block. Ten patients had a rise of serum enzymes. It seemed that in severe patients the serum enzymes rose markedly. From the analysis of laboratory and histological findings. Coxsackie B viral myocarditis were often complicated by hepatitis.