Intercostal artery laceration is an unusual complication following thoracentesis, and has been reported only in elderly patients. We report a case of a 78-year-old man who developed a massive hemothorax following thoracentesis. Post-thoracentesis radiograph revealed a substantial increase in pleural fluid, and emergency chest tube insertion identified the hemothorax. He underwent right thoracotomy for repair of the intercostal artery laceration.