Between 1977 and 1992, four infants with an anomalous left pulmonary artery and subsequent compression of the tracheobronchial tree were operated on at the University Hospital Zurich. The operation consisted of mobilization of the abnormal left pulmonary artery with reimplantation into the main pulmonary trunk in three patients; the left pulmonary artery was transected and restored in front of the trachea by end-to-end anastomosis in one. Mean follow-up was 7 years (range 2 months to 14.3 years). There were no early and no late deaths. All patients have shown significant symptomatic improvement without respiratory infection or disturbance of normal life activities. Surgical therapy in this rare condition can be safely undertaken with good long-term results. In symptomatic patients the operation should be performed early before occurrence of severe respiratory symptoms and bronchial collapse.