The analysis of feces is a fundamental tool for field work, especially to identify the presence of certain species in an area. Fecal bile acids and their relative concentration follow patterns that are species-specific, and can be characterized by Thin Layer Chromatography (TLC). This technique has been used for differentiating feces of several mammal species; however it has never been used for Xenarthra species. In this work, 96 feces of Xenarthra species were analyzed by TLC to determine the bile acid pattern. The species were: Zaedyus pichiy (n = 10), Chaetophractus vellerosus (n = 5), Chaetophractus villosus (n = 57), Dasypus kybridus (n = 4), Priodontes maximus (n = 2), Tamanduá tetradactyla (n = 14) and Myrmecophaga tridactyla (n = 4). There were differences between the bile acid patterns of all the species, but not between males and females, nor between wild and captive animals of the same species. We found seven known bile acids, cholesterol and seven unidentified compounds (X1-X7). All the species had taurocholic, glycochenodeoxycholic and lithocholic acids, and cholesterol. Only C. villosus had deoxycholic acid (Rf: 0.30 ± 0.01). Z. pichiy, C. vellerosus and C. villosus had two or three bands of dehydrocholic acid (Rf between 0.29 ± 0.06 and 0.45 ± 0.02), while the other species had one or two. Z. pichiy had two unidentified bile acids, X6 (Rf: 0.85 ± 0.06) and X7 (Rf 0.93 ± 0.03), that were almost indistinguishable in other species. D. hybridus differed from Z. pichiy, C. vellerosus and C villosus because it did not have chenodeoxycholic acid and X7. T. tetradactyla was the only species without cholic acid and it differed from M. tridactyla because it had dehydrocholic acid. D. hybridus was the species with the lowest number of compounds (seven), and differed from the others because it did not have the X1 and X5 unidentified compounds. These results are the first for Xenarthra and would be very important for fu ture studies about the conservation and the ecophysiology of the group.