We provide four news records of bats—Micronycteris hirsuta (Peters, 1869), Dermanura gnoma (Handley, 1987), Myotis riparius Handley, 1960, and Myotis lavali Moratelli, Peracchi, Dias and Oliveira, 2011 to the Piauí State, northestern Brazil. We also provide measurements and taxonomic comments about the species recorded. With these new records, 59 bat species are now recognized for the Piauí.
