Objective: To explore the vidian nerve anatomy by endoscopy and paranasal sinus computed tomography (CT) to elucidate the appropriate surgical approach based on preoperative CT images. Design: Retrospective analysis. Setting: Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. Patients: Sixty-seven patients underwent 106 endoscopic vidian neurectomies between January 9, 2006, and June 30, 2009. Main Outcome Measures: Paranasal sinus CT had been performed in all patients 2 weeks before surgery. Preoperative surgical planning was based on CT images, which were compared with intraoperative endoscopic findings. Two endoscopic approaches were used for vidian nerve transection, and the success rates were recorded for each. Results: The transsphenoidal approach was successful on 42 sides (39.6%), while the transnasal approach was successful on 91 sides (85.8%). Success rates for the transsphenoidal approach were 0.0%, 72.1% (31 of 43 sides), and 84.6% (11 of 1.3 sides) for canal corpus types I, 2, and 3, respectively. Success rates for the transsphenoidal approach were 50.0% (28 of 56 sides), 51..9% (14 of 27 sides), 0.0%, and 0.0% for canal floor relationship types 2, 3, and 4, respectively. The transsphenoidal approach was successful only in patients without an embedded canal and with a canal floor relationship type I or type 2. Presence of the septum and continuation of the canal bony structure also influenced the choice of surgical approach. Conclusions: The vidian nerve can be precisely identified and microinvasively transected using endoscopy. Preoperative CT images delineate the vidian canal and enhance preoperative surgical planning.