The objective of this study is to evaluate the short-term hearing results in tympanoplasty type 1 whether it is affected by mucosal condition of the middle ear cleft. Tympanoplasty type 1 was performed by one operator in 143 patients with chronic otitis media at Asan Medical Center between March 1990 and Feb 1993. The following results were obtained : 1) Preoperative air-bone gap was affected by the mucosal condition of mesotympanum. 2) Postoperative change of air-bone gap was affected by the mucosal condition of Eustachian tube orifice. 3) Successful graft rate in tympaoplasty type 1 was 95.8%. However, long-term follow-ups are needed for better evaluation of hearing results in tympanoplasty type 1.