The pulmonary artery sling is a vascular anomaly that produces severe respiratory disease in infancy. The differential diagnosis is lengthy, and the diagnostic work-up frequently includes such invasive maneuvers as bronchography, bronchoscopy, and cardiac catheterization. In this paper the use of a new noninvasive diagnostic tool, computer tomography, to aid in the diagnosis of this form of vascular ring, is discussed and a review of salient features of this cardiovascular malformation is presented.