A meta-analysis evaluated the impact of EEG-based monitoring of depth of anesthesia on postoperative delirium, cognitive dysfunction, and long-term neurocognitive outcomes. It included 17 studies with a total of 5,684 patients. Monitoring did not significantly affect duration of anesthesia, early postoperative Mini-Mental State Examination (MMSE) scores, or incidence of postoperative delirium before discharge. In the long-term follow-up, however, it significantly reduced the incidence of postoperative neurocognitive disorder. Patient satisfaction did not decrease significantly. Some analyzes showed high heterogeneity between studies. Monitoring has a protective effect against long-term neurocognitive impairment, especially in high-risk patients.