Description is given of five different types of anomalies of the great vessels in the superior mediastinum which can produce compression of the esophagus or trachea (or both). These malformations of the vascular system can give rise to difficulties in swallowing and to serious disturbances in pulmonary ventilation. These anomalies include double aortic arch, right aortic arch with a left ligamentum arteriosum, anomalous innominate artery, anomalous left common carotid artery, and an aberrant subclavian artery. The various symptom complexes which can be found with these anomalies are described. Endoscopic visualization of the interior of the esophagus or trachea gives valuable information in some cases. The investigation of these subjects should include fluoroscopic and film studies of the esophagus and trachea by contrast media. Data gathered from such roentgenologic examinations usually give a fairly clear idea of the type of vascular anomaly which is present. It is possible to attack surgically each of these vascular malformations. In general, the esophagus or trachea can be relieved by division of an anomalous vessel or by displacement of an artery in such a manner that it is carried away from the compressed structure. When necessary, these operative procedures can be undertaken in very young babies, even in the presence of a high degree of respiratory obstruction. All the operations have been through a left anterolateral, transpleural approach, under general anesthesia with a closed system. The results of operation in 40 patients are analyzed. It is evident that many vascular anomalies in the thorax which disturb the functions of the esophagus or trachea can now be treated with an excellent chance of relieving the obstructive symptoms.