Field studies in Colombia in 1959–1962 resulted in the collection of 245 specimens of 25 species of bats. These represented six families as follows: Emballonuridae, 2; Noctilionidae, 1; Phyllostomidae, 14; Desmodontidae, 1; Vespertilionidae, 3; Molossidae, 4. Additional records for two species ( Phyllostomus discolor , Lonchophylla robusta ) thought to be uncommon in Colombia are presented, and altitudinal ranges of several species ( Sturnira ludovici , Desmodus rotundas , Myotis nigricans , Tadarida brasiliensis , Eumops glaucinus ) are shown to be great in the western Andean region. Notes on distribution, variation, reproduction, food habits and general natural history are presented for many of the species.