We present a rare case of massive tongue necrosis occurring simultaneously with bilateral osteoradionecrosis (ORN) of the jaw in a patient with a history of treatment, including surgery and postoperative radiotherapy, for a retromolar trigone carcinoma 8 years earlier. There is a distinct possibility that the extractions and administration of local anesthesia with a vasoconstrictor contributed to the onset of ORN; together, these events may have influenced the blood supply to the tongue. A glossectomy was performed after hyperbaric oxygen therapy. One month after the surgical procedure, the patient responded satisfactorily to the treatment, showing significant improvement in speech and oral food intake, as well as significant decrease in lingual pain. Although the simultaneous occurrence of these oral complications is rare, the practitioner must be aware of the factors that instigate ORN and compromise vasculature as well as the clinical signs of tongue necrosis. Additionally, the possibility of tongue necrosis secondary to irradiation of the head and neck should be taken into consideration when an irradiated patient undergoes tooth extractions under local anesthesia with agents containing epinephrine.