We describe a 63-year old female patient presenting with increasing dyspnea on exertion. The chest X-ray was suggestive but not compelling for Ebstein's anomaly. Although Ebstein's anomaly is most often discovered first in childhood, rare cases, such as ours, are described in late adulthood, however. Obesity may be one reason why it was not possible in our patient to detect the characteristic features in transthoracic echocardiography. The diagnosis of Ebstein's anomaly could be established only by transesophageal echocardiography: There the right atrium was grossly enlarged due to the distal insertion of the septal tricuspid valve leaflet. Colour flow echocardiography clearly demonstrated severe tricuspid valve incompetence. No additional congenital or acquired cardiac disorder could be detected. Cardiac catheterization confirmed the echocardiographical findings, whereas magnetic resonance tomography did not show the abnormal insertion of the tricuspid valve leaflet. If Ebstein's anomaly is suspected and cannot be ascertained by transthoracic echocardiography, transesophageal echocardiography can be employed to definitely diagnose this fairly rare form of congenital heart disease in an adult population.