We report the results of small mammals inventories conducted in the region of Jaíba, northern Minas Gerais state, southeastern Brazil, from 1990 to 1995. This region is located in the southern limit of the Caatinga biome, and harbors a unique set of natural ecosystems and extensive agricultural areas. With a total effort of 2964 trap-nights and 44 net sessions, we captured 893 small mammals from 46 species, including four marsupials, 13 rodents, and 29 bats. We report on species that are endemic to the Caatinga (Wiedomys pyrrhorhinos and Xeronycteris vieirai), and species that are new to the mammal fauna of the state of Minas Gerais (Tonatia saurophila, X. vieirai, and Myotis lavali). We also provide the first valid voucher-supported record of Micronycteris sanborni from southeastern Brazil, and extend the known range of X. vieirai 800 km southward. All bats highlighted here as endemic or representing new records were associated to limestone outcrops, suggesting that preservation of this kind of habitat may be particularly relevant to the conservation of these mammals.