We report a case with an isolated single coronary artery originating from the ascending aorta, which to our knowledge has never been described before. A 51-year-old man presented for evaluation of atypical chest pain, suffering from a short resting chest pain for 3 days. However, serial electrocardiogram showed no change during chest pain. Cardiac enzymes such as CK-MB, Troponin-I, and myoglobin were within normal limit. Aortography and coronary angiography revealed a single coronary artery originating from the postero-lateral wall of the ascending aorta above the left coronary siuns. However, this anomaly was not of clinical significance based on the atypical nature of the chest pain, negative exercise echocardiography and an absence of obstruction of the coronary artery.