Coronary artery fistula and coronary artery-cardiac chamber shunts were observed in 16 cases out of 462 consecutive cases in which coronary angiography was performed. 9 of these cases had coronary artery fistula, 5 of the cases had coronary artery-cardiac chamber shunts. 2 cases had both of these conditions. Coronary artery fistula has a draining vein originating from the coronary artery and an entering vein terminating in the cardiac chamber or the pulmonary artery. Coronary artery-cardiac chamber shunts have no such veins, and contrast material used in the injection phase of coronary angiography escapes directly into the cardiac chamber. 2 cases of coronary artery fistula, 2 cases of coronary artery-cardiac chamber shunts, and 1 case involving the both of these conditions showed positive results in submaximal exercise tolerance tests, and no significant arteriosclerotic changes in the coronary artery. These factors lead us to suggest that coronary artery-cardiac chamber shunts cause cardiac ischemia for the same reason that coronary artery fistula does.