Penetrating atherosclerotic ulcers (PAU), aortic dissection, and intramural hematoma are the three most important diseases involving the aorta which are classified as acute aortic syndromes. Penetrating atherosclerotic aortic ulceration is characterized by ulceration of atheromatous plaque disrupting the internal elastic lamina. These aortic ulcers may penetrate through the media to cause aortic pseudoaneurysms or less often through the adventitia to cause transmural aortic rupture. We described a case of penetrating atherosclerotic ulcer of ascending aorta mimicking ST elevation myocardial infarction. To our knowledge, this is the first case reported in the literature of such a complication from PAU.