목적: We evaluated the advantages and outcomes of performing bilateral simultaneous middle ear surgery for chronic otitis media. For comprehensive analysis, we compared three subgroups, bilateral mastoidectomy(MM), unilateral mastoidectomy with contralateral tympanoplasty(MT), and bilateral tympanoplasty(TT). 방법:A total of 176 ears of 85 patients with chronic otitis media or cholesteatoma that underwent bilateral same-day surgery. The side with worse hearing was chosen for the first operation. In the absence of any intra-operative complications, the contralateral operation was then performed. 결과:. Results of hearing tests did not differ significantly among the three groups except for gained decibels in the TT versus MT groups (P=0.033). The correlation between pre-operative sound field audiometry (SFA) and post-operative SFA were statistical significant. These results indicate that low frequency hearing was recovered immediately, but middle and high frequencies recovered later. Temporary taste change differed statistically among the three groups (P=0.006). There were significantly more revision cases during the postoperative period in the groups that included mastoidectomy (MM group, MT group) (P=0.035). 결론:Bilateral simultaneous middle ear surgery provides good hearing outcomes, reduces costs and operation times, and has a low incidence of complications. The results of our study may be helpful in guiding the otologists decision when performing bilateral middle ear surgery. This work was accepted and epub ahead of print at EUROPIAN ACHIVES OF OTO-RHINO-LARYNGOLOGY