Background: Canal wall down mastoidectomy has many drawbacks including chronic otorrhea not responding to medications, granulations, dizziness on exposure to cold or hot water, and tendency of debris accumulation in the mastoid cavity, necissating periodic cleaning. Many of these proplems can be solved by reconstruction of the posterior meatal wall. Aim of work: To solve the cavity proplems after CWD mastoidectomy via reconstruction of posterior meatal wall, and to compare between the outcomes of the Bioglass versus titanium mesh in reconstruction of posterior meatal wall. Patients and methods: This study was applied on 40 patients that have chronic sappurative otitis media. All cases were subjected to canal wall down mastoid surgery with complete elimination of the disease and reconstruction of the posterior meatal wall. Patients were divided to 2 groups: group (A) was managed by canal wall down mastoidectomy with reconstruction of the posterior meatal wall by Bioglass and the group (B) was managed by canal wall down mastoidectomy with reconstruction of the posterior meatal wall by titanium micromesh; all patients were exposed to full preoperative evaluation, and full postoperative assessment of complications, appearance of the external auditory canal contour, and the hearing gain expressed by the change of the air bone gap postoperatively. Results: There is a significant difference between the two groups regarding postoperative complications mainly the postoperative granulations and discharge, the postoperative appearance of the external auditory canal contour, and the hearing gain in favor of group (A) but there is no significant difference between the 2 groups as regard the intraoperative difficulties, the other postoperative complications like wound infection, canal stenosis, extrusion or displacement of the materials and recurrence of cholesteatoma. Conclusion: Reconstruction of posterior canal wall can eliminate many of the cavity proplems after CWD mastoidectomy especially by using the Bioglass which shows better advantages than the titanium micromesh