Osteopetrosis is a heterogeneous group of skeletal disorders. It is a rare genetic disease caused by osteoclast dysfunction, leading to invalid bone desorption and remodeling and an increase in skeletal mass and density. We present the case of a 52-year-old female with osteopetrosis of the temporal bone. She reported loss of hearing in her left ear 14 years ago because of a head trauma. Four months ago, she was conservatively treated because of sudden sensorineural hearing loss in her right ear with no improvement. Her pure tone average audiogram was bilaterally 90 dB with 10% speech recognition. The patient was implanted with a cochlear implant. Except for the extremely thick and dense cortical bone of the mastoid, surgery was uneventful. Speech recognition 6 months after the surgery showed 75%. The results were stable for 3 years follow-up. Patients with profound hearing loss caused by osteopetrosis may benefit from cochlear implantation.