In the United States alone, nearly 6 million patients present annually to emergency departments with complaints of chest pain suggestive of acute coronary ischemia. Most of these patients have a non-negligible risk for acute coronary syndrome(s) (ACS) and undergo extended observation and workup for an ischemic cause. Of those admitted for extended observation, less than 30% of patients have true ACS. In patients with a low to intermediate probability, cardiac CT performs well in ruling out coronary artery disease, and American College of Cardiology and American Heart Association guidelines deem this application to be "appropriate." This article reviews the application of CT for the evaluation of acute chest pain the emergency department.