We report the case of an adolescent with post-verbal severe/profound sensorineural hearing loss, occurring as a consequence of two bouts of pneumococcal meningitis at 12 and 32 months of age. A possible immunodeficiency was investigated, revealing hereditary complement C2 deficiency (C2D). Given the insufficient benefit from high-power hearing aids, the boy received a cochlear implant (CI) at age 12. Despite the long interval of partial hearing deprivation and the postmeningitic etiology, improvement in open-set speech perception and quality of life were observed. The C2D did not favour post-operative infections nor meningitis recurrence. The risks and benefit of CI in this peculiar clinical circumstance are discussed after reviewing the literature.