Introduction. Otosclerosis is an osteodystrophy disease of the bony labyrinth of the ear which leads to stapes fixation and to bradyecoia of a conductive type. The microsurgical treatment by the use of a stapes prosthesis provides hearing improvement and a reduction or disappearing of tinnitus. The aim of our study was to determine the hearing condition and tinnitus before and after the treatment of otosclerosis. Material and methods. A hundred patients with otosclerosis, aged 20 to 70, were surgically treated at the Otorhinolaryngology Clinic and the Functional Diagnostics, Military Medical Academy, Belgrade. After the treatment, the audiometric examinations were performed in order to assess the hearing condition and tinnitus was assessed by a questionnaire. The subjective assessment of tinnitus was ranged as present, reduced or absent. Results. Before the treatment, hearing impairment was present in all the patients, while tinnitus was found in 91% of them. One year following the surgical treatment hearing improvement was found in 96% of the patients, and tinnitus cessation in 89% of them. Conclusion. The surgical treatment can result in hearing improvement and cessation or reduction of tinnitus.