OBJECTIVE To evaluate the clinical manifestation of Mondini dysplasia with cerebrospinal fluid leakage and investigate the effect of the surgical repair through trans-horizontal semicircular canal and vestibule approach. METHOD Four cases which were operated by the approach of trans-horizontal semicircular canal and vestibule in our hospital were analyzed retrospectively. RESULT The leakages were all stopped by the primary surgical closure after six-month follow up. CONCLUSION Mondini dysplasia should be considered in children or teenagers with recurrent bacterial meningitis whether or not with otorhinorrhea. Pure tone audiometry and a temporal bone CT or MRI will confirm the diagnosis. A trans-horizontal semicircular canal and vestibule approach is an effective and simple way for the treatment.