OBJECTIVESReconstruction following endoscopic skull base surgery requires a high degree of success to avoid the morbidity of postoperative cerebrospinal fluid (CSF) leak. The impact on outcomes of CSF visualization with intrathecal fluorescein, however, is unknown.STUDY DESIGNA retrospective review of patients undergoing endoscopic skull base surgery with intrathecal fluorescein. A possible correlation between intraoperative fluorescein identification and postoperative CSF leak was analyzed.RESULTS61 patients underwent surgery for a variety of lesions including pituitary adenoma (55.7%), encephalocele (14.8%), and meningioma (9.8%). Seven (19.4%) of the 37 patients with intraoperative fluorescein leak experienced postoperative CSF leak compared to 0 of the 24 patients who did not have intraoperative fluorescein leak (P = 0.02). All cases of CSF leak resolved with lumbar drainage alone.CONCLUSIONSThe lack of intraoperative fluorescein leak‐age correlates strongly with a low risk for postoperative CSF leak. This can be used to stratify the extent of skull base reconstruction required during endoscopic skull base surgeries.