Cerebrospinal fluid rhinorrhea is a rare disease on otolaryngologic field and is mostly caused by trauma. The case was a 19-year-old female who had taken bilateral Caldwell-Luc's operation with polypectomy at local clinic on August 12th, 1978. After then, right side watery rhinorrhea and intermittent headache had been noted so she visited our hospital on July 4th, 1979. On the Physical examination, small amount of clear watery discharge was seen on the right superior meatus. This fluid was proved as CSF by the chemical test and fluorescein study through spinal tapping. She was treated absolute bed rest and medication of high dosage of vitamines and sedatives for three weeks, but this treatment proved useless. The operation was done by transcranial intradural approach at department of Otolaryngology and cooperation of Neurosurgery. As the result of this operation, CSF rhinorrhea disappeared and we couldn't find any symptoms in follow-up study.