A 62-year-old man with hypertension and hypercholesterolemia was referred to our unit for evaluation of chest pain. A very rare variant of single coronary artery, in which the anomalous right coronary artery originated as a separate branch from the left anterior descending artery, was incidentally found on his coronary angiography. The anomalous right coronary artery in our case appears to be unique in that it courses intraseptally rather than rightwards proximally and has obstructive atherosclerotic lesions resulting in inferior ischemia. Moreover, the acute angle made by the anomalous right coronary artery to turn toward the atrioventricular groove may have reduced the flow velocity and contributed to the development of inferior ischemia.