The management of cholesteatoma relies primarily on surgical intervention, with canal-wall-up (CWU) and canal-wall-down (CWD) tympanomastoidectomy representing the main operative approaches. Despite meticulous removal, cholesteatoma remains associated with high rates of residual and recurrent disease. CWD procedures have been associated with reduced rates of recurrent disease, but the creation of a mastoidectomy cavity is fraught with the need of life-long ear debridement, regular office visits, and worse hearing outcome than CWU procedures. Two recent systematic reviews of mastoid obliteration case series reported 5‑year recurrence rates below 6%—a remarkable improvement compared with traditional non‑obliteration techniques. This course will review current literature on epitympanic and mastoid obliteration in the management of middle ear cholesteatoma, with focus on canal wall reconstruction in CWD mastoidectomy. The presenter will demonstrate his obliteration method in CWD mastoidectomy for reconstruction of the posterior canal wall to avoid a mastoidectomy cavity, highlighting key steps, potential pitfalls, postoperative imaging surveillance, and outcome data. The advantages and limitations of various obliteration materials—including autologous bone dust and active bioglass—will be discussed, along with indications for using temporoparietal fascia or periosteal flaps with axial blood supply to cover the filler material and promote optimal healing. The presentation will be enriched with intraoperative photographs and instructional videos.