A 68 yr-old male with evidence of persistent inferior wall ischemia after successful PTCA of a solitary right coronary artery (RCA) lesion was found to have an anomalous left circumflex artery (LCX) arising from the ostium of the RCA. The LCX harbored an atherosclerotic subtotal obstruction, which was then successfully dilated with resolution of the myocardial ischemia. Although not known to have a statistical predisposition to atherosclerotic disease, diseased anomalous coronary arteries can be responsible for myocardial ischemia and infarction. A thorough search for such vessels is warranted in patients with abnormal diagnostic tests and no apparent obstructive lesions in the normally positioned arteries. Similarly, when ischemia does not resolve after successful treatment of a coronary stenosis, anomalous coronary arteries should be sought.