Anomalous origin of a coronary artery is rare, but may represent a clinically significant abnormality, since some anomalies are associated with myocardial ischemia, infarction, and sudden death. Diagnosis may elude routine screening procedures, and even when an anomalous vessel is identified angiographically, it may be difficult to delineate its true course on the basis of angiography alone. The purpose of this study was to determine whether transesophageal echocardiography (TEE) is of value in making the diagnosis and outlining the course of anomalous coronary arteries. Five adult patients with anomalous origin of a coronary artery were studied by monoplane TEE and selective coronary angiography. Transthoracic echocardiography (TTE) was also performed in four of these five patients. Anomalous coronary ostia were visualized in four of five patients utilizing TEE, but in none of four patients by TTE. A proximal segment of the anomalous coronary vessel was identified in all five patients by TEE, and in only two of four patients by TEE. TEE images were consistently of superior diagnostic quality. TEE is a valuable tool for the echocardiographic identification of anomalous coronary arteries, and is superior to TTE in adult patients.