Coronary arterioventricular fistula is a rare form of congenital malformation of coronary artery. A 29-year-old man presented with a 4-year history of shortness of breath and recently developed chest discomfort during exertion. A huge, dilated coronary arterioventricular fistula from right coronary artery to left ventricle was diagnosed with transthoracic echocardiography, transesophageal echocardiography and coronary angiography. This finding was confirmed by selective administration of the microbubble into the right coronary artery during transthoracic echocardiography monitoring. The opening of the fistula at the level of left ventricle was obliterated with autologous pericardium and the patient recovered and discharged uneventfully.