A patient with chronic exertional angina and electrocardiographic signs of myocardial ischemia at exercise stress test had recent onset of rest chest pain and underwent coronary arteriography. Besides severe atherosclerotic coronary disease (which was probably responsible for clinical presentation), a single coronary artery arising from the left sinus of Valsalva was discovered. This is an exceptional finding, and its in-life diagnosis may be relevant for surgical treatment.