The Mexican free-tailed bat, Tadarida brasiliensis mexicana, is one of the most widely distributed bats, and its range includes the whole Mexican territory. Ectoparasites of this bat have been the subject of isolated reports, but no studies of its community ecology have been conducted. The acarine infracommunities associated with this bat were analyzed, comparing bat populations from three and regions of Mexico: an abandoned factory in Nombre de Dios, Durango
a cave in Santiago, Nuevo Leon
and a church in Concepcion del Oro, Zacatecas. The acarine infracommunity in Nuevo Leon's bats exhibited the highest levels of diversity as reflected by a higher richness, a lower dominance, and a moderate and relatively homogeneous abundance in this locality in relation to the other two. This pattern is influenced by stable cave conditions relative to artificial habitats. Not withstanding, further studies are required to determine whether or not different habitat conditions are a primary factor in the process of structuring the acari infracommunities.