Methods: In a clinical trial study 62 patients with perforated tympanic membrane were selected and randomly divided in the two groups of 31. The first group was operated by overlay and the second group was operated by underlay tympanoplasty. All patients were followed in 3 and 6 months after surgery and improvement of the hearing, tympanic membrane land marks and post operative complications were compared between the two groups.

Findings: Three and six months after surgery, tympanic landmarks in both groups improved but there was no significant difference between the two groups but improvement of hearing threshold in frequencies of 1000 and 4000 was better in the overlay graft. The overall improvement in the overlay graft was 83.8% and in the underlay graft was 64.5% and no statistically significant difference was observed between the two groups (p=0.21).

Discussion: Our study showed improvement of hearing, success rate of operation, recurrence, and post operative complications were not different between overlay and underlay tympanoplasty methods. But the improvement of hearing in some frequencies was better in overlay method, although overlay tympanoplasty is more difficult. But if sufficient precision is given in this method itwill be safe and provides more favorable hearing results.

Keywords: Tympanoplasty; Overlay and underlay graft; Hearing Improvement