Background: Osteoradionecrosis (ORN) is defined as an area of exposed necrotic bone, in an area previously irradiated, that fails to heal over a period of 3–6 months in the absence of recurrence of tumour. ORN of mandible, though rare, is a serious and dreaded complication of radiotherapy. Aim: To study the role of hyperbaric oxygen therapy (HBOT) as an adjunct in improving outcome of treatment of ORN of mandible. Material and Methods: A retrospective analysis was done, from 2015-2017, of various head, neck and oral cancer patients who developed ORN and were treated with HBOT at our centre. The subjects underwent 30 sessions of 2.4ATA for 60min, five times a week in a monoplace hyperbaric chamber. The parameters observed, both pre and post HBOT were wound healing, pain relief and overall wellbeing. Results: The study included 80 patients with a mean patient age of 53.5yrs. 24 (30%) patients improved with HBOT alone. However, 37(46.25%) patients required sequestrectomy and 19 (23.75%) underwent surgery for resection/flap cover along with HBOT. Further 10-15 sittings of HBOT were given to them post-operatively. Conclusion: HBOT alone and as an adjunct to surgery shows encouraging results. Our study corroborates the existing literature on the potential benefit of HBO as a adjunctive treatment of ORN.