A 36-year-old man with a history of left upper lobectomy for empyema when he was four presented to the emergency department with subsequent intubation for acute respiratory failure. A post-intubation radiograph of the chest showed an opacity in the left lower lung zone, mediastinal shift to the left side with hyperinflated right hemithorax, and the presence of pleural lines with lack of lung markings in the periphery bilaterally (Fig. 1a). A computed tomography of the chest showed a large area of herniated right lung into the left thoracic cavity across the anterior mediastinum. There was prompt resolution of the bilateral pneumothorax after an emergency right tube thoracostomy (Fig. 1b). The left main bronchus was occluded, with severely atelectatic or hypoplastic left lung (Fig. 2). The radiographically residual left lung was actually the anatomically herniated right lung and the bilateral intrapleural air accumulation developed as a result of pneumothorax of the hyperinflated right lung.