Thirty-four years old man and fourty-one years old man were suddenly died after exercise and drinking, respectively. Autopsy and microscopic examinations showed severe cardiac dilatation and fibrosis in both cases. Myocardial degeneration was observed only in the former case. Decreased (diffusion) or increased staining for calmodulin was observed in association with contraction band necrosis. The decrease and increase in calmodulin staining is thought to represent necrosis and calcium-overload, respectively. Both cases were diagnosed to have died from dilated cardiomyopathy without particular histories and causes.