Although conventional intraoral surgery for masseteric hypertrophy is a useful technique, it is considerably difficult to resect the mandibular angle due to the narrow visual field. For the purpose of compensating for the drawbacks of this procedure, we performed endoscope-assisted intraoral surgery on 5 patients with bilateral masseteric hypertrophy, who were successfully treated. The use of an endoscope offers a clear view of the mandibular angle region, thus facilitating accurate and easy resection of the spur.