It is generally recognized that the optic surgical navigation system is a useful tool that provides accurate anatomical information in neurosurgery and orthopedic surgery. However, at present, this system is not used in maxillofacial surgery in Japan. We report a patient with postoperative maxillary cyst treated by cystectomy using an optical navigation system. A 68-year-old female visited our department due to swelling in the right maxillary area. CT scanning showed a cystic lesion extending from the maxillary tuberosity to the nasal cavity. The lesion was surgically resected using an optical navigation system. In this patient, the use of a navigation system allowed objective confirmation of the portion of the lesion close to the nasal cavity and that surrounding the root of the second molar. In the future, the optic navigation system is expected to become a useful tool for safe and accurate surgery by oral surgeons.