Abstract Objective To compare Clinical-Functional Vulnerability Index-20 (IVCF-20) and Edmonton Frail Scale (EFS) scores among community-dwelling older people aged ≥80 years for prevalence and degree of agreement. Method A cross-sectional study nested within a population-based cohort, was conducted. Baseline sampling was probabilistic by two-stage clustering. In the first stage, the census tract was used as the sampling unit. In the second stage, the number of households was defined according to the population density of individuals aged ≥60 years. Sensitivity, specificity and predictive values were determined and Kappa statistics expressed degree of agreement between the instruments. Results 92 oldest-old people were evaluated. The prevalence of high risk of clinical and functional vulnerability on the IVCF, indicating frailty, was 45,7%, whereas the prevalence of frailty using the EFS was 44,6%. Sensitivity, specificity, positive predictive value and negative predictive values were 88,23%, 87,80%, 90,0% and 85,71%, respectively. Accuracy was 88,04% and the Kappa statistic 0.759 (p<0.001). Conclusion The IVCF-20 and EFS instruments showed good accuracy and strong agreement when applied to community-dwelling oldest-old people. The identification of frailty was superior using the IVCF-20. These results show that the instruments detected similar frailty prevalence in community-dwelling oldest-old people.