Congenital fusion of the jaws (syngnathia) is a rare and severe disorder. The authors report a case of bony fusion of the left mandible with the maxilla and zygomatic complex in a 5-day-old male who was not able to feed and open his mouth normally. Early surgery was performed to release the bony fusion on the tenth day of life. The authors present a new technique based on the intraoperative use of 3-dimensional surgical guides.