CT-guided lung biopsy is now widely performed for tumorous lesions in the lung, and both its usefulness in this context and the associated complications have been well described in the literature. Although severe complications are rare, we describe a case in which massive intrathoracic haemorrhage developed after lung biopsy and necessitated emergency operation for control. Intraoperative findings suggested that the source of the haemorrhage was a fibrous, cord-like substance present at the site of adhesion associated with old tuberculosis. We attributed this haemorrhage to a pneumothorax, which developed after lung biopsy and caused the new vessels penetrating the centre of the fibrous, cord-like substance to stretch and rupture. Numerous cases have been reported of spontaneous haemopneumothorax precipitated by spontaneous pneumothorax and resulting from the rupture of such vessels.