In large internal carotid artery (ICA) aneurysms, the angle of the mandible becomes an anatomical obstacle to creating an adequate access. Widening the access can be achieved by performing a mandibular osteotomy.Case report. A 70-year-old female patient was admitted to hospital with complaints of hoarseness of voice, dyspnoea and congestion of the right ear. Objective examination revealed nasal respiratory distress due to nasopharyngeal compression by a voluminous mass, mild dysarthria, dysphonia, tongue deviation to the right, paresis of the right soft palate and right vocal cord. Computed tomography and magnetic resonance imaging showed a 50×49×60 mm thrombosed ICA aneurysm in the carotid space. Surgical management was performed by a multidisciplinary team including neurosurgeons, otolaryngologists and maxillofacial surgeons. Extended access was achieved by intraoral mandibular osteotomy followed by mobilization. Early postoperative resolution of neurological symptoms was observed.Discussion. To gain access to giant aneurysms of the cervical branch of the ICA, it is possible to use the technique of intraoral osteotomy of the mandible. This reduces trauma and the risk of complications, while increasing the radicality of the main stage.