Lung volvulus is a rare occurrence and is most commonly seen after thoracic surgery or trauma. They are generally associated with a long, thin hilum, with no parenchymal bridge between the lobes. In non-postoperative situations, pleural effusion or pneumothorax would appear to be mandatory. Spontaneous volvuli are not described, especially sub-acutely. We report the case of a patient with an apparently spontaneous lung volvulus. He presented with long prodromal symptoms of haemoptysis and increasing cough. The computed tomography scan showed a complete volvulus of the right lung with signs of non-perfusion of the upper and middle lobes. The patient was successfully treated with volvulus reduction and bi-lobectomy. Torsion is classically known to thoracic surgeons, but is rarely encountered by other specialists. We describe here a sub-acute lung volvulus, apparently spontaneous, easily treated by a simple surgical procedure.