Cochlear fibrosis is defined as a formation of fibrous tissue within the fluid-filled spaces of the inner ear. Usually fibrosis progresses to cochlear ossification. It was happened from various etiologies. Cochlear fibrosis could be detected in MR images however, suspicion was crucial. Fibrosis of scala tympani was a problematic condition for cochlear implantation especially using straight type electrode array. We recently examined a 73-year-old woman presenting with bilateral profound sensorineural hearing loss. She had left hearing loss since her childhood and the right side hearing loss with dizziness was started after the ear surgery 2 months ago. Temporal bone CT showed soft tissues in middle ear and mastoid. Stapes was subluxated to vestibule. MR imaging showed narrowing of scala tympani of basal turn. Since the right hearing loss had relatively recent onset, we decided to do the CI on her right ear. During operation, there was mild fibrosis in the scala tympani, Implantation was performed using Contour electrode array with stylet. Postoperative examination of imaging, impedance and neural response telemetry showed well introduced electrode and good function.