Surgical findings and long-term results of 112 revision operations performed for failures after cholesteatoma surgery were studied. The indication for revision was recurrence of cholesteatoma in 43 percent, persistent otorrhea in 27 percent, dry reperforation in 10 percent, and unsatisfactory hearing result in 18 percent. Of the recurrences, 71 percent were regarded as residual cholesteatomas (i.e., arising from a cholesteatoma remnant left at the primary operation). Infected unexenterated mastoid air cells were found in 63 percent of ears reoperated on for persistent discharge. Thus, it is reasonable to conclude that at least 48 percent of our revisions could have been avoided if the surgeon had used more skillful and more radical surgical technique when performing the primary operation. On the other hand, the persistence of cholesteatoma and the difficulty of eradicating the disease is highlighted by the finding that cholesteatoma again recurred in three patients (3%) after the first revision.