Results of 45 re-operations for persistent or recurrent conductive deafness after primary stapes surgery were studied. The mean follow-up period after the revision surgery was 7.6 years. Long-term hearing results were found to be disappointing, air-bone gap to within 10 dB was achieved in only 46 per cent of the patients. Mean hearing levels improved by 11 dB or more in 73 per cent. Outcome of surgery was dependent on the surgical pathology, the best hearing results were obtained in cases with re-fixation after stapes mobilization operation. Sensorineural hearing loss as a result of surgical trauma to the inner ear occurred in revision surgery more frequently than in primary operations, cases with regrowth of otosclerotic bone to the oval window after stapedectomy having the greatest risk of labyrinthine trauma.