Coronary artery fistulas (CAFs) are rare congenital or acquired abnormalities that have anomalous terminations of the coronary arteries. Although many patients with CAFs are asymptomatic, they can display various clinical features associated with ischemic heart disease or heart failure. Making an early diagnosis is important for the proper management and prevention of late symptoms and complications. Conventional coronary angiography and cardiac CT have been commonly performed to diagnose CAFs, but multi-detector computed tomography (MDCT) is now being widely applied for diagnosing cardiovascular anomalies, and the number of incidentally detected CAFs on MDCT has been increasing. Therefore, we have to be familiar with the image findings of CAFs, and especially the image findings of MDCT for making the correct diagnosis of CAFs. In this article, we illustrate the MDCT findings of various types of CAFs in adults and we review the pathophysiology and clinical features of CAFs.