Objective: To determine if there is a hearing gain after performing a tympanoplasty type 1 in patients with mid level chronic otitis and conductive hearing loss. Material and Methods: This study was conducted in the otolaryngology service of the Specialty Hospital Nº2, highly specialized medical unit, Northwest National Medical Center in Obregon city, Sonora. A study of a retrospective, analytical and longuitudinal cohort was carried out. Overview of the Study: Clinical records of patients diagnosed with sequale of mid level chronic otitis, tympanoplasty type 1 post surgery patients in this institution from March 2011 to April 2014 were reviewed. Data such age, sex and place of origin were taken and if there were any post surgery complications, average level of hearing previous and after surgery. Results: From a total of 237 reviewed patients, 51 were completed, of which 33 were female ...