Objective: Chronic empyaema deteriorates lung function and causes thoracic asymmetry due to intercostal narrowing in the diseased hemithorax. This study aims to investigate the rates of improvement in the pulmonary function tests (PFTs) and the thoracic deformity in late postoperative period of lung decortication, performed for chronic empyaema. Methods: A total of 50 patients who underwent standard open decortication for empyaema were included. The PFTs and computed tomographic (CT) scans of the chest were analysed in all patients after 6-58 months postoperatively. The measurements of antero-posterior and transverse diameters of both hemithoraxes were performed on both preoperative and postoperative chest CTs. The thoracic asymmetry was calculated as the ratio of the measurements of the diseased side to the normal side. The pre- and postoperative parameters were compared statistically. Results: The mean preoperative forced expiratory volume in first second (FEV1) and forced vital capacity (FVC) increased from 61.40% and 60.89% to 78.92% and 77.48%, respectively, in the late postoperative period (p < 0.001). The mean preoperative transverse diameter of affected hemithorax increased from 11.22 cm to 11.98 cm (p < 0.001) and, the transverse asymmetry improved from 11.52% to 5.94%, postoperatively (p < 0.001). The mean preoperative antero-posterior chest diameter improved from 15.58 cm to 16.67 cm (p < 0.001), and the antero-posterior asymmetry improved from 11.42% to 5.42% (p < 0.001) in the late postoperative period. Conclusions: The open decortication for chronic pleural empyaema significantly increases FEV1 and FVC. Due to the re-expansion of the lung and enlargement of the intercostal spaces, the chest wall deformity also improves considerably after the operation. (C) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.