Objectives: The present study was designed as a trial to improve field visibility during functional endoscopic sinus surgery (FESS) by means of positional changes and the use of controlled hypotension achieved through maintenance of anesthesia using remifentanil and either of propofol infusion (Total Intravenous; TI) or isoflurane inhalation (Combined Intravenous/Inhalational; CII). Patients & Methods: The study included 32 patients; 23 males and 9 females, with mean age of 39.2±8.4 years and assigned to undergo FESS. Patients were divided randomly into two equal groups according maintenance anesthetic regimen: Group TI and Group CII. Each group was subdivided according to patients position during surgery into supine and anti-Trendelenburg by 30o. Anesthesia was maintained in both groups by slow infusion of 2 mg of remifentanil in 40 cc of physiological saline in addition to 50 cc of propofol infusion in Group TI group or isoflurane 1-2% in Group CII. Patients were monitored non-invasively; before induction of anesthesia (T0) and 20 (T20), 40 (T40) and 60 min (T60) after induction of anesthesia, for mean arterial pressure (MAP) and heart rate (HR). The approach for FESS was conducted totally endonasal after Kennedy procedure. The visibility of the operative field during FESS was evaluated using 6-points Fromme scale and total amount of bleeding as judged by the amount evacuated was also recorded. Results: Both anesthetic modalities reduced blood pressure significantly and decreased heart rate throughout times of observation compared to preoperative levels with significantly lower MAP measures in anti-Trendelenburg compared to supine position. All surgeries were conducted completely without intraoperative complications and no extensive bleeding was recorded. There was a significant increase in the frequency of good field visibility with TI compared to CII anesthesia with significantly improved field visibility in patients maintained in anti-Trendelenburg position compared to supine position. Estimated mean blood loss was significantly less and the recorded field visibility scores were significantly higher in TI group compared to CII group. There was a negative significant correlation between the field visibility score and mean MAP and mean amount of bleeding. Using regression analysis, the use of hypotensive anesthesia was found to be a significant independent factor for improving filed visibility, and the use of TI anesthesia was found to be significant determinant independent factor for induction of hypotensive anesthesia. Using ROC curve defined the superiority of use of TI over CII anesthesia as independent determinant for field visibility. Conclusion: It could be concluded that maintaining patients in anti-Trendelenburg position and anesthetic manipulation using total intravenous anesthesia could minimize bleeding and improve field visibility during FESS and thus this combination of manipulations could be appropriate strategy for such type of surgery.