Cerebrospial fluid rhinorrhea is rare and often a difficult diagnostic problem for the physician. The diagnosis of CSF rhinorrhea was aided by history and physical examination, followed by analysis of the nasal fluid, radiography including tomography, and dyes with fluorescein study. Radionuclide cisternography has become a useful method for localization, but now CT is widely used because this modality has the advantages of easy performance, noninvasiveness, high resolution and density differentiation. A 45-year-old male patient was admitted to our hospital with a chief complaint of profuse leakage of fluid from his left nostril following head trauma by traffic accident. Radioisotope cisternogram and CT scan were performed, and revealed abnormal figures in left frontal area, which is surggestive of CSF fistula. We report this case with review of literatures.