Reported is a case of single coronary arterial anomaly (SCAA) with its origin from the right sinus of Valsalva as demonstrated by selective coronary arteriography. No branches coursed between the great vessels. Electrocardiography and vectorcardiography were consistent with inferior wall myocardial infarction, although subsequent coronary arteriograms were free of luminal narrowing. While this is an infrequently recognized isolated coronary anomaly, it may carry significant risk of myocardial ishcemia. This risk may not depend alone upon the passage of a branch of SCAA between the great vessels. Evidence of precocious ischemic heart disease should alert the angiographer to look for anomalous coronary anatomy.