A model of autoimmune myocarditis was developed in guinea pigs. The disease was induced by repeated subcutaneous administration of heterologous myocardial tissue and adjuvants. After immunization all experimental animals developed myocarditis, mostly of diffuse but also of focal character of the inflammatory process. The model of the disease can be used to study immunological and metabolic processes occurring in the course of myocarditis. (Fig. 2, Ref. 16.)