목적: The effect of intratympanic(IT) steroid injection on sudden hearing loss has already been proven. Although each studies differ in opinion, its effectiveness as a salvage treatment and as a concomitant treatment is usually accepted. However, there's still debate on whether IT steroid injection alone can become an effective treatment for treating ISSNHL. On the basis that there's no reason not to prescribe oral steroids even till now, oral steroid is the standard treatment for patients with ISSNHL. In many cases, after considering the outcome of oral steroid treatment on patients with ISSNHL, an additional treatment such as IT steroid injection is performed. We would like to compare the results we have gained from by performing the oral steroid treatment, and additionally started the IT steroid injection which overlaps a few days during the oral steroid treatment on patients who show no sign of recovery 2wks after the onset of ISSNHL, to the results obtained from the groups that have started the IT steroid injection after the oral steroid treatment had ended. 방법:Among the 154 patients who have visited our institution and have received the IT steroid injection treatment during the period between Oct. 2010 till Jan. 2015, we have analyzed through the use of the medical records retrospectively the 95 patients who have undergone oral steroid tx. and have additionally received IT steroid injection and were able to obtain the PTA score before and after the treatment. 결과:Among them, 33 patients(Group A) had undergone the IT steroid injection treatment within 2wks after the onset of the disease while the other 62 patients(group B) had received the therapy 2wks or more after the onset of the disease. The average PTA score gained before the treatment for group A was 88.45±23.35 dB HL while that of group B was 69.58±30.33 dB HL. Group A had 18 out of 33 cases(54.5%) where there was more than 15dB recovery in PTA score that was tested after the treatment while that of group B had 20 out of 62(32.2%) which showed a difference of significance. If Siegel's criteria was applied to group A, 1/2/15 cases would fit in to I/II/III while for those of group B 2/1/17 cases would fit in to I/II/III. 결론:The time at which additional treatment such as IT steroid injection has started at the end of the oral steroid treatment could influence the outcome of the treatment. And starting additional treatment like IT steroid injection within 2wks after the onset of the ISSNHL showed better results than starting the additional treatment more than 2wks later after the onset of the disease.