Purpose: This study aimed to evaluate the effect of controlled hypotension on cerebral oxygen saturation and postoperative cognitive dysfunction (POCD) in patients undergoing nasal surgery.,Materials and Methods: Forty patients were randomized by a sealed envelope method into two drug groups: esmolol (Group E, n=20) or nitroglycerin (Group N, n=20) administration prior to surgical incision. The cognitive functions of the patients were evaluated by the Mini-Mental State Examination Test 1 day before and 1 day after the operation. Regional oxygen saturation was monitored with near-infrared spectroscopy to detect cerebral desaturation.,Results: The desired mean arterial blood pressure (50-65 mmHg) could be achieved in all groups. A decline in cognitive function occured in 16 patients (40%) at the 24th postoperative hour. There was no statistically significant difference between the groups in terms of POCD. There was a significant relationship between POCD and cerebral desaturation status.,Conclusion: Cerebral desaturation seen during hypotensive anesthesia may cause early POCD development, therefore we think that close cerebral and hemodynamic monitoring during hypotensive anesthesia may preserve cognitive functions.