A coronary artery fistula is a communication between a coronary artery and a cardiac chamber or vein. It is a rare congenital anomaly seen in 0.1%-0.2% of coronary angiograms. Those that drain into the left side of the heart are even rarer: only 5% of fistulas drain into the left atrium, 3% into the left ventricle. The author reports a patient presenting with easy fatigability, palpitations, and chest heaviness on exertion. Imaging done at the Philippine Heart Center revealed a coronary arterial fistula from the left coronary artery via the left circumflex artery draining to the coronary sinus a left atrium. Plan is to do ligation of the anomaly.