When a patient with COPD is admitted with acute exacerbation of dyspnea and chest x ray shows unilateral hyper translucency, most likely diagnosis is pneumothorax. Rarely other conditions may radiologically mimic pneumothorax. Treatment of pneumothorax in AECOPD is intercostal tube drain. But intercostal tube drain in other conditions which mimic pneumothorax radiologically can lead to complications. We discuss a case of translucent hemithorax in a patient with AECOPD which was mistaken for pneumothorax. Subject Area: Respiratory medicine Keywords: Unilateral hyper translucency; Bulla; Intercostal tube drain; AECOPD