A 66-year-old man presented with Ebstein's anomaly associated with left ventricular dysfunction. He had been followed since 40 years of age for cardiomegaly and arrhythmia, and experienced episodes of orthopnea at the age of 64. He was referred to our hospital in April 1997 because of lower extremity edema. Physical examination revealed dilated external jugular vein, tenderness of the right hypocondorium, and lower extremity edema. Electrocardiography confirmed atrial fibrillation. Transthoracic echocardiography revealed bilateral atrial and ventricular dilation, and paradoxical septal movement. The apical four-chamber view demonstrated 15 mm apical displacement of the septal leaflet. Color Doppler echocardiography revealed moderate tricuspid regurgitation. Transesophageal echocardiography revealed low echoic and hypoplastic tricuspid valve. Left ventriculography showed diffuse hypokinesis, and the ejection fraction was 49%. The coronary artery was normal. Atrial septal defect was not detected. Diffuse fibrosis, which may be found in the hearts of patients with Ebstein's anomaly at autopsy may have been responsible for the left ventricular depressed systolic function in this patient.