An isolated single coronary artery from the left aortic sinus is one of rare congenital coronary anomalies. This anomaly was detected during elective coronary angiogram in a 44 year-old male patient with atypical chest pain. Treadmill exercise test demonstrated 1 mm horizontal depression at stage IV and the test was terminated at the V stage due to chest pain. No myocardial ischemia was demonstrated on myocardial SPECT using 99mTc-tetrofosmin. Coronary angiogram revealed single coronary artery originating from left aortic sinus without any stenotic lesions.