We experienced an extremely rare complication during performance of laparoscopic totally extraperitoneal (TEP) inguinal hernia repair for a 57-year-old healthy man. About 50 minutes after CO₂ insufflation, the patient developed tachycardia, hypoxemia, hypercapnia and an increased airway pressure. Right pneumothorax with subcutaneous emphysema was recognized on the emergency chest X-ray and this was successfully treated by chest tube insertion. Anesthesiologists should be aware of the possible occurrence of pneumothorax during laparoscopic TEP hernia repair.