Preoperative risk assessment may fail in most patients who may be exposed to postoperative neurological sequelae. The aim of this study was to assess the effects of Fentanyl added to epidural levobupivacaine on cerebral oxygenation and cognitive functions. There was a negative correlation between age and MMT, and a positive correlation between SpO2 and MMT. MMT scores of Group 2 at postoperative first hour and fifth hours were lower than those of Group 1. It was concluded that while fentanyl added to epidural local anesthetic had no effect on hemodynamic parameters, SpO2, and right-left cerebral oxygen saturation, and although it may have caused a decrease in MMT scores in the early postoperative period, it did not cause impairment in cognitive functions.