Resumo. Permanent preservation areas contribute to the recovery of impacted environments and Formicidae is a potentially bioindicator group, used to describe the structural complexity of habitats. In this context, the study aimed to characterize the diversity of ant assemblages that occur in sites with different soil use history in the APP of Foz do Chapecó HPP reservoir, as well as to evaluate the similarity of ant assemblages according to the sampled sites. Sampling was carried out in January 2017 at five sites, three in Santa Catarina state and two in Rio Grande do Sul state. Pitfall, entomological umbrella, sardine bait, glucose bait and manual collection were used. Assemblies were characterized and compared through richness, abundance, diversity of Shannon-Weaver (H’), Equitability (J’) and estimated richness (Chao 1). A total of 101 species were sampled. The average of the estimates indicated that richness may be 86.7% greater than that sampled, while the diversity parameters indicated differences between the assemblies. Diversity indices showed divergence of 39.7% between the more and less diverse assemblies. The richness observed in this study reiterates the potential of the use of ants as bioindicators of the state of environmental conservation, adds important information on the richness and occurrence of ants for the region and presents, above all, an inventory of the species of ants present in an area of APP in a regeneration process that can serve as parameter for subsequent evaluations.