Coronary artery disease (CAD) is the number one cause of death in the United States, and it is estimated that every 40 seconds one person experiences a heart attack. Among patients with chronic CAD, many will experience a potentially fatal complication known as acute coronary syndrome (ACS). Wellens syndrome is a rare form of ACS that indicates critical left anterior descending coronary artery occlusion and can be identified by its characteristic T-wave patterns on ECG. This syndrome also may go unrecognized by clinicians because of a lack of familiarity with the ECG findings. This article describes the Wellens ECG pattern and its significance in patients with chest pain.