This paper describes two cases of left ventricular aneurysm following myocardial infarction by real time B mode echocardiography with a mechanical sector scan. The most distinctive feature was the paradoxical movement of the aneurysmal wall; in systole, it moved posteriorly to form a bulge, whereas the remaining noinfarcted area was oriented toward the left ventricular cavity in contraction. The final diagnosis was verified by aneurysmectomy.