This study evaluates the ability of metrizamide computerized tomographic cisternography (MCTC) to delineate the site of leakage in patients with cerebrospinal fluid (CSF) rhinorrhea. From 1981 to 1986, thirteen patients were examined by MCTC to localize the site of CSF leakage. A total of 17 studies were performed. Thirteen scans (76%) identified the site of CSF leakage. Nine of these scans were confirmed surgically. The other four scans were performed on patients who refused surgery. Of the 15 scans in patients with active CSF leaks, 13 (87%) were positive. Of the two patients with inactive CSF leaks, neither was positive. One patient is presented in whom MCTC was both diagnostic and therapeutic. In conclusion, MCTC has a high success rate in localizing the site of active CSF leaks.