Objective To evaluate the relationship between grandparenting and the cognitive impairment in older persons. Methods The protocol was submitted to the International Prospective Register of Systematic Reviews (PROSPERO), registration number: CRD42018105849. Authors conducted a systematic review, following “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) recommendations. Electronic databases were accessed through august 2018: PubMed, ISI Web of Knowledge, Scopus, and EBSCOhost. Selection of records and quality appraisal were made by two reviewers, independently. Results A total of 178 records was found, after removing duplicates. From those, 17 were considered eligible for integral text reading and eight were included: five original studies, one classic review and two editorials. From the five original studies included, four suggested a positive effect on cognition resulting from grandparenting and one suggested that there was no evidence for a causal effect. Though the boundary was not consensual, some studies suggested that a higher frequency of grandparenting has a negative impact on cognition. Conclusion Overall, studies suggested a trend towards a positive effect of grandchild care on grandparents’ cognition. However, there was a significant heterogeneity between methodologies and a significant risk of bias which can hamper conclusions, indicating the need for further and more robust research. Psychiatry Investig 2021;18(7):593-602