Caviomorpha or South American hystricognaths are taxonomical and ecological diverse rodents with broad dietary habits, ranging from frugivorous to grass eaters. The oldest fossil record of the group dates back to the late middle Eocene of Peru. Continuous paleontological field efforts increase the knowledge and diversity of most ancient species, testifying a rich and complex early evolutionary history. However, little is known regarding the ecology of these Paleogene caviomorphs and its impact on the early evolution of the group.In this work we analyze the teeth enamel surface of extant caviomorphs in order to assess if their different dietary habits are reflected by distinct microwear textures. This approach aims to obtain a model to be applied to paleoecological studies.The method, named dental microwear texture analysis (DMTA), describes and analyzes automatically surface textures, with a high degree of precision. In the last decade, various studies from several authors explore its application yet this work is the first to look at caviomorph rodents. We studied 90 specimens representing 15 species and 4 families of extant caviomorphs with different feeding habits all coming from the state of Rio de Janeiro, Brazil. For each specimen, we performed a scan on a high resolution silicon mold of the occlusal surface of the first upper molar with aLeica DCM8 optical surface profilometerat the IPHEP lab (CNRS and University of Poitiers, France). Then we applied a scale-sensitive fractal analysis with Toothfrax and Sfrax softwares to describe the microwear textures through five variables: Asfc (complexity), epLsar (anisotropy), HAsfc (heterogeneity of the complexity), Smc (scale of maximum complexity) and TFV (textural fill volume). Our results indicate that there is significant microwear texture differences between primarily frugivorous and grass-eater species.These preliminary results on living species demonstrate that the DMTA method represents a potentially powerful analytic tool for reconstructing the diet of extinct species of caviomorphs.