ABSTRACT Bats and ectoparasites, Streblidae and Nycteribiidae, are good models to study ecological interactions due to their specificity. Knowledge about the interactions between these groups is heterogeneous and fragmented throughout Brazilian territory, mainly in the southern region – influenced by the temperate climate with bat fauna presenting elements from both tropical and temperate areas. We evaluated the interaction of parasites and bats in an Atlantic Forest area, southern Brazil. We captured bats and their ectoparasites monthly in 10 campaigns using mist nets. To describe the interactions, we used prevalence and average intensity of infestation, the same indexes we used to compare host sexes. We captured 494 bats, from which 151 had ectoparasites. Artibeus lituratus and Sturnira lilium were the most abundant bat species. We captured 303 ectoparasites, from which Metelasmus wenzeli is a new record to the state of Santa Catarina. Paratrichobius longicrus and Megistopoda proxima were the most abundant ectoparasite species, probably due to the greatest abundances of the host species of bats A. lituratus and S. lilium in this study. Most of the interactions we found are primary associations, which reinforces the specific parasite–host relationship. The data we obtained here are the first for the state of Santa Catarina.