The anaesthetic experiences and problems have been analysed, based on 100 orthognathic operations. The material includes all kinds of operations; operating time was about 4 hours, except for 8 very extensive procedures, lasting 6--7 hours. The importance of adequate premedication is emphasized. The use of nasal drops for decongestion is especially highly recommended for the prevention of bleeding during nasal intubation. An armoured nasal tube is always used; however, special care must be taken to detect leaks on the cuff. On four occasions the tubes had to be changed because of leaks in the cuff. The most annoying complication was tachycardia, due to: insufficient premedication, insufficient analgesics during operation, or the use of hypotensive drugs. Blood loss was clearly diminished by controlled hypotension. Postoperative vomiting was prevented by the use of a nasogastric tube for the first 6--8 hours. Major complications were not encountered.