The electrocardiogram (ECG) has being used for decades as a reliable and inexpensive tool to diagnose acute myocardial infarction (AMI). ECG diagnosis of an occluded coronary artery is of the utmost importance. We present the case of a 46 year-old man admitted to our hospital for inferior AMI. The ECG findings suggested right coronary artery occlusion. Coronary angiography showed left circumflex artery occlusion. We also briefly review the literature.