A case of inner ear anomaly (Mondini dysplasia) associated with recurrent meningitis found in a 10 year-old boy is reported. The patient had suffered from bacterial meningitis and CSF rhinorrhea five times in 7 years. The origin of CSF leakage had not been detected by bifrontal craniotomy or trans-sphenoidal operation. In May 1985, the dysplasia of the temporal bone and the inner ear had been pointed out by an otologist. And he underwent operations a few times for closing the CSF fistula at the floor of the internal auditory meatus by translabyrinthine approaches, but in vain. On the 7th of November 1985, under the control of intracranial pressure by continuous ventricular drainage, re-operation was performed. Packing the internal auditory meatus with several pieces of muscle and gelatine sponge stopped the CSF leakage and the recurrence of meningitis.