AbstractOlder persons experiencing a longer length of stay (LOS) or delayed discharge (DD) may see a decline in their health and well-being, generating significant costs. This review aimed to identify evidence on the impact of cognitive impairment (CI) on acute care hospital LOS/DD. A scoping review of studies examining the association between CI and LOS/DD was performed. We searched six databases; two reviewers independently screened references until November 2019. A narrative synthesis was used to answer the research question; 58 studies were included of which 33 found a positive association between CI and LOS or DD, 8 studies had mixed results, 3 found an inverse relationship, and 14 showed an indirect link between CI-related syndromes and LOS/DD. Thus, cognitive impairment seemed to be frequently associated with increased LOS/DD. Future research should consider CI together with other risks for LOS/DD and also focus on explaining the association between the two.