This study reports the evaluation of the results after 72 stapedotomies in patients with bilateral otosclerosis. All pre- and postoperative audiological data, together with all relevant information of the operations, were stored in a data base and analyzed retrospectively. The Glasgow benefit plot (GBP) is a useful method to evaluate the hearing results of each individual ear after stapes surgery in a more functional way rather than from a technical standpoint. Therefore, it has been used to assess the benefit obtained after second-ear stapedotomy. From the results it appears that a second operation on the contralateral side increases the chances of achieving at least one ‘normal’-hearing ear, and it makes symmetrical ‘normal’ hearing possible in the majority of the cases.