Twelve children were evaluated 7.1 years (mean) after surgical repair of a vascular ring causing tracheal compression. Nine patients complained of persistent respiratory symptoms, mostly cough, dyspnea, and/or wheezing. Functional evaluation revealed abnormal spirometry and/or lung volumes in seven subjects. Analysis of maximal expiratory-inspiratory flow-volume loops suggested the presence of residual upper airway obstruction in three patients and peripheral airway obstruction in three others. Eleven patients demonstrated bronchial hyperreactivity to histamine.