We present the results of a three-year study on the bat species killed by wind turbines at the Osorio Wind Farm, a large wind power complex in southern Brazil, and compare these fatalities to the composition of the local bat fauna. Fatality searches around wind turbines were conducted from 2006 to 2009, as well as a bat inventory through mist-netting and searches for colonies from 2004 to 2010. We found a total of 336 bat fatalities: Tadarida brasiliensis (n = 245), Lasiurus cinereus (n = 44), Nyctinomops laticaudatus (n = 12), Molossus molossus (n = 9), Lasiurus blossevillii (n = 6), Promops nasutus (n = 3), Lasiurus ega (n = 3), Molossus rufus (n = 1), and Artibeus lituratus (n = 1). By mist-netting, we recorded 13 bat species in the region, of which only six were killed by wind turbines. Our results are similar to mortality patterns from the Northern Hemisphere in terms of: (1) uneven distribution of fatalities among species; (2) dominance of migratory species, including foliage/tree-roosting bats; and (3) discrepancy between presence and abundance of species recorded in the wind farm area and in the fatality sample.