Aims: To assess the diagnostic accuracy of the Finnish Diabetes Risk Score (FINDRISC) for undiagnosed T2DM and to compare its performance with the Latin-American FINDRISC (LA-FINDRISC) and the Peruvian Risk Score. Materials and methods: A population-based study was conducted. T2DM and undiagnosed T2DM were defined using oral glucose tolerance test (OGTT). Risk scores assessed were FINDRISC, LA-FINDRISC and Peruvian Risk Score. Diagnostic accuracy of risk scores was estimated using the c-statistic and the area under the ROC curve (aROC). A simplified version of FINDRISC was also derived. Results: Data from 1609 individuals, mean age 48.2 (SD: 10.6), 810 (50.3%) women, were collected. A total of 176 (11.0%; 95%CI: 9.4%–12.5%) were classified as having T2DM, and 71 (4.7%; 95%CI: 3.7%–5.8%) were classified as having undiagnosed T2DM. Diagnostic accuracy of the FINDRISC (aROC = 0.69), LA-FINDRISC (aROC = 0.68), and Peruvian Risk Score (aROC = 0.64) was similar (p = 0.15). The simplified FINDRISC, with 4 variables, had a slightly better performance (aROC = 0.71) than the other scores. Conclusion: The performance of FINDRISC, LA-FINDRISC and Peruvian Risk Score for undiagnosed T2DM was similar. A simplified FINDRISC can perform as well or better for undiagnosed T2DM. The FINDRISC may be useful to detect cases of undiagnosed T2DM in resource-constrained settings.