We describe a patient with effort angina in whom the coronary arteriography revealed a rare type of coronary arterial fistula. All three major coronary arteries communicated with the left ventricle through a plexus of thin vessels. Both exercise stress test and thallium-dipiridamol demonstrated reversible myocardial ischemia. We think this case supports the clinical significance of the coronary steal phenomenon induced by the coronary arterial fistulae.