Objective: To describe the characteristics and distribution of triatomine fauna in rural communities of Simplício Mendes municipality, located in the state of Piauí, Brazilian semiarid region. Methods: This is a cross-sectional study and entomological survey conducted from 2022 to 2023. Insects were captured using active search method in all human dwellings, which were georeferenced, followed by characterized of species, sex, developmental stage, and identification of presence of infection by trypanosomatids. Results: All households (n=178) in 10 rural localities of the municipality were investigated, resulting in a household triatomine infestation rate of 14%. A total of 268 insects were collected, predominantly species from the Triatoma brasiliensis complex (n=190), immature developmental stage (n=172), and originating from peridomestic environments (n=250). The rate of triatomines with natural infection by Trypanosoma cruzi was 1.1%. Conclusion: The finding of infestation by species from the T. brasiliensis complex with higher concentration cohabiting extradomestic spaces, wide dispersion, and presence of natural infection by T. cruzi signals conditions for the maintenance of vector-borne transmission of Chagas disease in the municipality.