Objective To systematically evaluate the prevalence of diabetes in older adults with frailty.Methods PubMed, EMbase, Web of Science, CNKI, CBM, VIP and WanFang Data databases were electronically searched to collect cross-sectional studies about the prevalence of diabetes in older patients with frailty from inception to November 2020. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies; then, meta-analysis was performed by using Stata 15.0 software.Results A total of 21 cross-sectional studies involving 22 403 subjects were included. The pooled prevalence of diabetes in older patients with frailty was 34% (95%CI 26% to 43%). Subgroup analysis showed that the prevalence of diabetes in patients with frailty in Asia and South America were higher than those in Europe and North America. The prevalence of diabetes in patients with frailty using physical frailty measures to evaluate frailty was higher than using multidimensional frailty measures. The prevalence of diabetes in patients with frailty in outpatient and hospital were higher than in community.Conclusion Current evidence suggests that the prevalence of diabetes is high in older adults with diabetes.