Coronary arteriovenous fistula is a more prevalent, hemodynamically significant congenital malformation. Both coronary arteries arise normally from their aortic sinuses, but the branches of fistula communicate directly with cardiac chamber, pulmonary trunk, coronary sinus, superior vena cava, or pulmonary vein. Fistula associated with coronary aneurysm is an uncommon finding. We report a rare case of 76-year-old female patient who had a coronary arteriovenous fistula with giant coronary artery aneurysm. This case is clearly diagnosed by echocardiography, three-dimensional computed tomography (3D-CT), and coronary angiography (CAG).