Sensorineural hearing loss is a condition in which the cochlea (the hearing organ in the ear) or the nerve pathways for hearing are damaged. A cochlear implant is a device that acts in place of the damaged inner ear to help communicate sound to the brain. At present, the Ontario government funds one cochlear implant for people who have hearing loss in both ears. This health technology assessment evaluates the potential benefits and harms of having cochlear implants in both ears (bilateral cochlear implantation) as opposed to just one, and whether this is good value for money. We also talked to people with sensorineural hearing loss about their values, preferences, and experiences with cochlear implants.