A case of a 10-month-old boy with a cerebrospinal fluid (CSF) fistula in his right ear is reported. In the same ear, the patient also showed congenital inner ear dysplasia. The CSF fistula was obstructed surgically. Surgical exploration showed a fistula superior to the oval window and a normally shaped stapes. The stapes was removed and the fistula was closed by obliteration of the vestibulum with the temporal fascia and fat tissue. The location of the fistula was very rare; to our knowledge, this is the first reported case of CSF fistula superior to the oval window. The relationship between perilymphatic fistula and the microfissure revealed by temporal bone study is discussed.