During the years 1979-81, three different surgical techniques were used in the treatment of 87 ears with extensive cholesteatoma. All procedures were performed in one stage by the same surgeon. Ten to 13 years after the operations about 70 per cent of ears operated on by the canal wall up technique had developed a new cholesteatoma, which in most cases was recurrent, or a deep retraction pocket. A modification of this technique with mastoid obliteration resulted in a similar failure rate. In contrast, ears operated on by the canal wall down technique (in most cases with mastoid obliteration) had acceptable stability with a long-term recurrence rate of about 15 per cent. Most patients in the canal wall down group had a dry ear without significant cavity problems. Hearing in these patients was as least as good as hearing in patients with a preserved canal wall. We conclude that a meticulous one-stage canal wall down technique in ears with extensive cholesteatoma results in a high percentage of unproblematic, stable ears with satisfactory function. In contrast, if the posterior canal wall is preserved, recurrent cholestealoma is the rule more than the exception.