Acute rupture of the interventricular septum is a relatively unusual complication following acute myocardial infarction. The echocardiographic features depicted by transthoracic echocardiography are well described. However, transesophageal echocardiographic description of a ruptured septum has not been previously reported. This brief report illustrates the transesophageal features of such a defect. (Chest 1993; 103:1884-85)