Sudden sensorineural hearing loss is a disease that develops within several hours to several days and its etiology is not verified yet. Therefore no specific regimen is available for the treatment of this disease. In 1980, Wilson reported that the corticosteroid was effective on the treatment of patients with sudden sensorineural hearing loss. However others reported the different results regarding the effect of the corticosteroid on the recovery of sudden sensorineural hearing loss. And many variables are involved in the evaluation of the therapeutic effect of this disease, such as age, degree of hearing loss, accompanying symptoms, interval between onset of disease and initial treatment, etc. The purpose of this study is to seek the therapeutic effect of the corticosteroid on the sudden sensorineural hearing loss of 64 patients(66 ears) admitted in Severance Hospital from September 1985 to August 1989. Sixty-six ears were divided into the control(34ears) and experimental(32 ears) groups. The control group did not received the steroid therapy and Prednisolone was given orally in the experimental group(tapering from 60mg to 10mg for 10days). The therapeutic effect of steroid was analyzed according to the variables affecting the evaluation of its effect and Man-Whitney & Wilcoxon Rank Sum W tests were used for statistical analysis. 1) There was no statistical correlation between the age and recovery rate(p>0.05). 2) If initial hearing loss was moderate or severe in severity, the recovery rate of the experimental group was better than that of the control group(p<0.05). 3) When the patient was seen within 7days, the recovery rate of the experimental group(81.3%) was better than that of the control group(27.3%) significantly(p<0.05). 4) In the patients who had vertigo as a accompanying symptom, the recovery rate of the experimental group(62.5%) was better than of the control group(22.2%). But there was no statistical significance(p<0.05). 5) In the patients whose audiograms were ascending, flat and descending in configuration, the recovery rates of the experimental group(100%, 66.7%, 100%) were better than those of the control group(66.7%, 33.3%, 33.3%) significantly(p<0.05). 6) In the patients with URI history, the recovery rate of the experimental group(90%) was better than that of the control group(28.6%) significantly(p<0.05). 7) Total recovery rate of the experimental group(68.7%) was better than that of the control group(41.2%) significantly(p<0.05). Present results suggest that the corticosteroid therapy seems to be effective on the hearing recovery of sudden sensorineural hearing loss, especially in case who had a URI history prior to onset of hearing loss, whose hearing loss were moderate or severe in severity, who had no vertigo as a accompanying symptom, and who received the initial treatment within 7days after onset of this disease.