This study compared the hearing outcome of canal-up and canal-down mastoidectomies for removal of cholesteatoma in 455 ears. An intact canal wall procedure was performed in 92 patients while the remainder (N = 363) underwent a canal-down operation. The hearing results for both procedures are dependent on the presence of the stapes superstructure. When the stapes superstructure was intact, 52% of the patients with canal-up operations had an air-bone gap of less than 20 dB. The corresponding figure for canal-down cases was 37%. When there was no stapes superstructure, 54% of the canal-up cases and 19% of the canal-down cases obtained a similar ABG closure. Preserving the posterior external auditory canal wall results in slightly better hearing function. However, when the stapes superstructure is intact, the difference in hearing function is not remarkable, and must be weighed against the potential for residual disease or recurrence associated with canal-up procedures.