The mandibular coronoid hyperplasia can be classified as a congenital or development change of the temporomandibular joint. This condition occurs due to a no-neoplasic growth of the coronoid process to the infratemporal fossa. Thus, this part of the bone impacts in the posterior face of the zygomatic bone causing limitation of the mouth opening. The aim of this paper is to report a clinical case of a 43-year-old male with mouth-opening limitation 28 years ago. After clinical and computed tomographic examinations, he was diagnosed with bilateral mandibular coronoid hyperplasia. The treatment proposed was a bilateral coronoidectomy by intraoral approach. In a 1-month postoperative period, the patient reported improvement of the painful complaints and mouth opening. After 1 year, the patient recovered the mouth opening improving his quality of life and there were no more complaints.