Paradoxical embolism is a rare cause of myocardial infarction. We present a case of a young man who was admitted to our hospital with an inferior myocardial infarction. Coronary arteriography showed a total distal occlusion of a posterolateral branch of the circumflex artery. Contrast-enhanced echocardiography showed a large atrial septal aneurysm with a patent foramen ovale and massive right-to-left shunting. No other sources of cardiac embolism could be identified. In this case, paradoxical embolism probably has resulted in myocardial infarction.