Endolymphatic hydrops has been documented as a possible complication of cochlear implantation; however, few studies have addressed its treatment. We describe the first case ever reported of delayed endolymphatic hydrops after a cochlear implant successfully treated with intratympanic gentamicin injection. A detailed discussion of this case with a focus on its management and outcomes will be provided in comparison with literature data. The intratympanic gentamicin injection has been demonstrated to be an effective treatment for symptomatic endolymphatic hydrops after cochlear implantation. We advocate further studies to validate this strategy as a promising alternative to surgical labyrinthectomy.