Radionecrosis of the larynx is a debilitating disease associated with pain, dysphagia, respiratory obstruction, and, in some cases, the need for laryngectomy. Persistent poor wound healing can lead to death. A series of eight patients with advanced (grades III and IV, Chandler classification) radionecrosis of the larynx treated with adjunctive hyperbaric oxygen therapy is presented. Signs and symptoms of radionecrosis were dramatically ameliorated in seven of eight patients, while one patient, despite subjective improvement, eventually required laryngectomy. There were no deaths. These results are compared to previous series on radionecrosis of the larynx in which hyperbaric oxygen was not used. This series indicates that hyperbaric oxygen therapy is a useful and effective adjunctive treatment modality in the management of laryngeal radionecrosis.