Objective: To review the outcome in consecutive patients who have undergone complete epitympanic and mastoid obliteration and concurrent tympanic membrane reconstruction over a 53-month period. Study Design: Retrospective review. Setting: Tertiary referral center. Patients: Sixty-two ears in 56 sequential patients undergoing mastoid obliteration with major indications including recurrent infection, debris trapping in the canal wall-down cavity, intolerance of water exposure, calorically induced vertigo in an existing cavity, a semicircular canal fistula, and inability to wear a hearing device. Thirty-six ears in 33 patients who underwent second-stage surgery for ossicular reconstruction during the same time period are also reviewed. Intervention: Transplanted autogenous cranial bone is used to induce osteoneogenesis resulting in complete obliteration of the epitympanic and mastoid spaces while maintaining a mesotympanic space. Main Outcome Measures: Success of obliteration, incidence of symptoms prompting intervention, hearing outcome, incidence of recurrent cholesteatoma, and incidence of eustachian tube dysfunction necessitating treatment and need for revision surgical procedures. Results: Complete take of the bony obliteration occurs in over 95% of cases; 90% of treated patients enjoy complete absence of original symptoms, whereas symptoms improved in the remainder. For over 95% of patients. existing eustachian tube function has been adequate after obliteration. To date, no patient has required revision surgical intervention. Conclusion: Mastoid obliteration with autogenous cranial bone is a safe and extremely effective option for treatment of problematic canal wall-down mastoid cavities. Surgical techniques that include sterile harvest of the cranial bone graft mixed with antibiotic, revision of the cavity to expose viable native bone, inclusion of the epitympanic spaces in the obliteration, and complete coverage of the pAte with autogenous fascia have proven critical to successful outcome.