Methods This study will be a systematic review of published studies that report the frequency of cognitive changes after non-cardiac surgery. We prepared the protocol in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines12 and registered it on PROSPERO (CRD42022370674). If important changes to the study methods are implemented, the PROSPERO record will be updated before the publication of the final results, to reflect these amendments.