We investigated the hearing recovery in 51 patients with sudden deafness with the initial averaged five-frequency hearing levels worse than or equal to 100 dB. Twenty-two patients were treated in an outpatient setting with a peri-oral steroid, vasodilator, metabolic activator, and vitamin B. The remaining 29 patients were treated in the hospital with additional hyperbaric oxygenation therapy and/or Satellite ganglion block. The results were as follows. 1) The ultimate averaged five-frequency hearing levels were mainly distributed from 55 to 80 dB. Only seven patients showed ultimate hearing levels worse than 100 dB. Two patients achieved complete recovery better than 20 dB. 2) There was no significant difference in the hearing recovery between the patients treated in an outpatient setting and in the hospital. 3) The time interval until the hearing recovery began was distributed broadly between 2 and 28 days from the onset. While most of the patients who began to recover within 14 days from the onset showed ultimate hearing levels better than 80 dB, the patients who recovered after 14 days had worse hearing levels.