The left pulmonary artery sling (LPAS) is a rare vascular anomaly causing respiratory distress in which the left pulmonary artery arises from the posterior aspect of the right pulmonary artery,courses posteriorly to the right of the bronchus and passes between the trachea and oesophagus to reach the hilum of the left lung.The LPAS is frequently associated with tracheobronchial tree anomalies and congenital cardiac defects.Proper assessment of the tracheobronchial and cardiovascular anomaly is essential in LPAS for planning management of the patient.Currently,the most important prognostic factor is considered to be an associated tracheobronchial tree anomaly.1 The purpose of this study was to demonstrate the role of multi-detector computed tomography (MDCT) for diagnosing LPAS and assessing the anatomical relationship with tracheobronchial tree anomaly.