Twenty-six patients underwent pleural decortication for chronic empyema. All had a computed tomgraphy scan of the chest showing no marked parenchymal destruction. Multiple subpleural linear densities perpendicular to the pleura were seen to various degrees and the sum of the areas of these densities was evaluated for each patient. The thickness of visceral and parietal pleura, nodularity of the empyema wall, presence of calcification, and homogeneity of the inner content of the empyema were assessed. The degree of lung reexpansion was quantified from the ratio of the aerated areas of the affected and unaffected lungs on postoperative chest radiography. Successful lung reexpansion was achieved in 23 patients. The 3 patients in whom lung reexpansion failed required a subsequent pneumonectomy. The thickness of extrapleural fat and the sum of the areas of subpleural linear densities were significantly higher in these 3 patients. In the successful decortication group, the degree of lung reexpansion correlated with the sum of subpleural linear densities and with a noted homogeneity of the inner content of the empyema. Computed tomography appeared to be useful in determining the appropriate surgical method of treating chronic empyema.