Tension pneumothorax is a rare complication during anesthesia and ventilating bronchoscopy. The authors have experienced a case of tension pneumothorax during ventilating bronchoscopy for removal of a foreign body(peanut) in the left mian bronches which caused cardiac arrest in a 22 month old pt. The patients was successfully resuscitated by CPR and closed thoracostomy. Subsequently the foreigh body was removed by bronchotomy.