Congenital coronary artery fistulas (CAFs) are rare. Some patients develop symptoms of congestive heart failure secondary to a large left-to-right shunt or myocardial ischemia from coronary artery steal in the first few years after birth. After the second decade the frequency of symptoms and complications increase. We report a case of CAF originating from the circumflex artery and draining into the coronary sinus, associated with left main coronary aneurysm. Transtho-racic and transesophageal echocardiography approach showed the origin, course, and drainage site of the CAF. This case represents a typical sample of this rare anomaly and puts into evidence the essential role of echocardiography to define and complete the angiographic diagnosis.