Sudden sensorineural hearing loss is defined as an acute hearing reduction of 30 dB or more, in at least three consecutive frequencies, occurring within 3 days of symptom onset. There is no consensus on the best treatment option. The aims of this paper were to evaluate the effectiveness of a treatment protocol based on medical therapy combined with hyperbaric oxygen therapy and to examine the factors that influence the recovery of hearing (age, gender, the amount of time between the onset of symptoms and the initiation of treatment – time since onset –, audiometric curve type and objective vertigo). Audiometric results were evaluated according to Siegel’s criteria. In patients treated also with hyperbaric oxygen therapy we observed complete resolution in 44.1% of the patients, partial resolution in 37.2%, slight improvement in 10.5% and no improvement in 8.2% of the patients. This resolution pattern was significantly different from that observed in the patients treated only with medical therapy. The factors associated with a better prognosis were young age, rapid intervention, upward sloping or pantonal audiometric patterns and the absence of objective vertigo. Gender appeared to be an insignificant factor. Medical treatment associated with hyperbaric oxygen therapy gives better results in terms of hearing gain compared to exclusive medical treatment.