Spontaneous CSF otorrhea is a rare condition, and about forty cases have been described in the literature to date. Here a case of spontaneous CSF otorrhea is reported.A 37-year-old man had suffered from recurrent bacterial meningitis and CSF otorrhea. Left mastoidectomy was carried out on May, 1989, by an otologist in the other hospital, but the origin of CSF leakage coudn't be identified. The patient was admitted to our hospital on January, 1990, to treat CSF otorrhea. Left temporal craniotomy was carried out. A dural defect was found in the left middle cranial fossa connecting to a bony defect at the left tegmen tympani. The defect was repaired by packing the tegmen tympani with fascia and fatty tissues. CSF otorrhea completely disappeared postoperatively.Spontaneous CSF otorrhea should be considered as a cause of recurrent bacterial meningitis. High resolution CT scan and MRI will be very useful in the diagnosis of this rare problem.