BACKGROUND:Tympanoplasty is a surgical technique for the reconstruction of the middle ear hearing mechanism but lack of an aerating mastoid  may be a significant source of failure.Aim :To determine the success rate of healing a tympanic membrane perforation after tympanoplasty alone or with cortical mastoidectomy .Materials and methods:This prospective study was conducted in the department of otorhinolaryngology SKIMS medical college and hospital. Adults Patients > 20 years of age were included.Total no. of 90 patients were taken in the study. The patients were divided into 3 groups(30 patients in each) . Group A  <2 episodes of discharge/year over a period of 3 years , Group B  2–4 episodes of discharge/ year over a period of 3 years .Group C  > 5 episodes of discharge/ year over a period of 3 years . In all 3 groups patients were divided randomly in two subgroups of 15 each,15  underwent tympanoplasty alone and 15 underwent tympanoplasty with cortical mastoidectomy. Temporalis fascia graft was used for repair of tympanic membrane perforation and all patients were followed up at regular interval. Data obtained was analysed according to Chi square test and paired t–test.Results:Of the 90 cases from all the 3Groups , 45 underwent Tympanoplasty alone and 45  underwent tympanoplasty with  cortical mastoidectomy.In Group A and Group B the results did not show any statistical significance, however in Group C patients resuls were statistically better when cortical mastoidectomy was done in combination with tympanoplasty. Conclusion:The Cortical mastoidectomy with tympanoplasty gives statistically no significant benefit over tympanoplasty alone in majority of patients. However it should be seriously considered in the patients who have a history of repeated episodes of active disease prior to surgery.