We report 5 patients, who had no cardiac abnormalities at their initial evaluation but progressed to dilated cardiomyopathy (DCM) during a mean follow-up period of 8.2 years. Their echocardiograms revealed increases in left ventricular (LV) end-diastolic dimensions, deterioration of LV contractions, and reduction in the LV wall thickness. Electrocardiographic changes were developed of rhythm disturbances, intensified ST-segment and T-wave changes, and the prolonged QRS durations. These findings, especially those of electrocardiography, seemed to be important for an early detection and characterization of DCM.