Chiroptera is the second largest order of mammals in terms of species richness, yet little data are available on the helminth fauna infecting bats. The goal of this paper was therefore to describe the helminth fauna of a common bat species from the Brazilian state of Rio Grande do Sul. We collected 63 individuals of the bat Tadarida brasiliensis in the municipality of Montenegro in March 2015 (33 males and 30 females; 41 adults and 22 juveniles). We identified 451 endoparasites belonging to eight species (i.e. Urotrema scabridum, Limatulum oklahomense, Postorchigenes paraguayensis, Parabascus limatulus, Ochoterenatrema sp., Vampirolepis decipiens, Tadaridanema delicatus, as well as one unidentified species representing the superfamily Microphalloidea). Based on their importance value, we classified two helminth species as ‘dominant’, four as ‘co-dominant’ and two as ‘subordinate'. Vampirolepis decipiens had both the highest prevalence (of 55.5%) and greatest abundance (3.52 parasites/host). We report for the first time P. limatulus in T. brasiliensis in Rio Grande do Sul. This study provides important base-line data to elucidate helminth infestations in T. brasiliensis in Brazil.