<p>This study evaluates modern and archaeological intra- and interindividual variability in stable isotope values (δ¹³C_coll and δ¹⁵N) of the armadillo species <i>Chaetophractus villosus</i> and <i>Dasypus hybridus</i> from east-central Argentina. Our goals are to contribute to the isotopic ecology of these species, assess the methodological implications of analyzing different skeletal elements, and contribute to the framework for the paleodietary reconstructions of hunter-gatherers in the region. We analyzed 20 modern samples obtained from carcasses collected during naturalistic taphonomic surveys in the Pampas. For each individual, one osteoderm and one endoskeletal element were analyzed. The isotopic values obtained from both elements are similar, supporting the use of osteoderms in isotopic studies due to their higher taxonomic diagnostic potential. Both <i>C. villosus</i> and <i>D. hybridus</i> exhibit wide interindividual variation in δ¹³C_coll and δ¹⁵N values, likely reflecting their omnivorous diets. When compared with available archaeological isotopic data for armadillos (N = 6), no major differences in isotopic niche space were observed. The overlap of armadillo isotopic signatures with those of other omnivorous taxa, and their separation from species with distinct diets or foraging strategies, supports the utility of isotopic analysis for identifying broad taxonomic contributions to human paleodiets in east-central Argentina. </p>