ObjectiveEndoscope-guided round window membrane repair was performed to evaluate whether the approach is feasible in the treatment of a round window fistula.Study DesignRetrospective case review.SettingTertiary care academic center.PatientA 27-year-old man had been scuba diving 6 days previously in the Australian Great Barrier Reefs. He had poor hearing with tinnitus in the left ear and a vertiginous sensation.InterventionA myringotomy was incised, and a tympanoscope was introduced into the middle ear cavity. With the patient under general anesthesia, the middle ear and the oval and round window areas were examined with a tympanoscope. In endoscopic visualization, a round perforation could be seen in the round window membrane. After detection of the round window perforation, a small piece of temporal fascia was obtained to seal the membrane perforation.ResultsOne month after the operation, the patient's hearing was significantly better. The myringotomy had healed.ConclusionA transmyringeal endoscopic procedure for round window fistula repair is feasible and combines the best features of minimally invasive surgery and aural endoscopy.