Coronary artery fistulae are rare anatomic anomalies that may be congenital or acquired. The most commonly affected vessel is the right coronary artery while origination from the left circumflex is rare. A coronary fistula creates a left-to-right shunt eventually leading to ventricular overload and congestive heart failure. Due to the low incidence of coronary fistulae, data is limited with regards to treatment strategies. We report the successful treatment of a large fistulous communication between the circumflex artery and the right atrium by proximal and distal ligation of the circumflex artery and selective revascularization of the excluded marginal branch.