To present the results of our experience with labyrinthotomy or vestibulotomy in cases where the oval window is blocked by the facial nerve and in the presence of bilateral congenital agenesis of the oval window, respectively. Retrospective analysis of the records of the patients operated in two different centers. Between 2007 and 2012, 5 ears of 4 patients who were operated on in two different clinics with a presumptive diagnosis of otosclerosis were included in the study. There were 3 female patients and 1 male. The ages ranged from 10 to 26 (mean 19 years). All patients had unilateral conductive hearing loss except 1 (10-year-old girl or patient 1). Pure tone averages were calculated at the frequencies 0.5, 1, 2 and 4 kHz both pre- and postoperatively according to the Committee on Hearing and Equilibrium 1995 Guidelines for the Evaluation of Results of Treatment of Conductive Hearing Loss. All patients underwent a middle ear exploration and postoperatively the initial audiological examination was performed after 6 months. Retrospective analysis revealed that vestibulotomy or labyrinthotomy was performed in 5 ears of 4 patients. Postoperative dizziness was encountered in 2 patients who had vestibulotomy due to oval window agenesis, which ceased spontaneously at 1 month postoperatively. The perioperative period was otherwise uneventful. None of the patients had sensorineural hearing loss or deterioration of hearing. There was a significant improvement in hearing after the operation. A 28-dB improvement in the mean air conduction pure tone thresholds was achieved. Vestibulotomy and labyrinthotomy are safe and effective procedures in terms of hearing restoration, which can be applied in cases of congenital agenesis of the oval window or obstruction of the oval window by the facial nerve.