Duchenne's progressive muscular dystrophy (DMD) is a genetic muscle disorder that causes degeneration and atrophy of the systemic and cardiac muscle. The disease is manifested early in childhood, and most of patients die by age 20 years of respiratory failure or heart failure. The cardiac involvement in DMD is characterized pathologically by degeneration and fibrosis of the myocardium, centering around the posterolateral wall of the left ventricle. Functionally, an abnormal electrocardiogram, valve motion, wall thickness, and wall motion are observed. Furthermore, abnormalities in plasma levels of atrial natriuretic peptide and autonomic function are also demonstrated. In this review, the cardiac involvements in DMD in the following aspects are described: 1) Electrocardiogram; a) high-frequency notches on the QRS complexes, b) amplitude of QRS complexes, c) late potential, d) arrhythmias, e) heart rate variability, f) a 10-year follow-up study, 2) Echocardiographic findings, 3) Hemodynamic findings, 4) Atrial natriuretic peptide.(Jpn Heart J 1997; 38: 163-180)