Genetic defects of the mitochondrial DNA often cause sensorineural hearing impairment, accompaniment by disorders of organs within the body. This case report describes cochlear implantation of a 33-year-old deaf blind female with mitochondrial cytopathy. The outcome was very successful, and vastly improved quality of life for this patient. Many cases of mitochondrial cytopathy cause progressive deafness; it is, therefore, likely that other patients with this unusual disorder will present for cochlear implant assessment.