Rupture of interventricular septum is an infrequent but serious complication of acute myocardial infarction. We report the cases of two patients admitted to our department for acute myocardial infarction whose clinical course was complicated by rupture of the interventricular septum. They died from cardiogenic shock on the 13th and 6th days. Two dimensional and color coded echocardiography correctly detected the presence and the site of the rupture.