During the 5-month dry season, I studied the community structure of bats in the Neotropical savanna of Espíritu, Bolivia. This seasonally inundated, grassland-dominated savanna is inhabited by ≥38 species of bats, and diversity is high (H′ = 2.88). Species richness is highest in forest islands (26 species), open woodlands and gallery forests (11 species each), and dense thorny bushes (7 species) and less in other plant associations. Although species from almost all trophic guilds filled by New World bats occur in the area, small medium-size low-flying insectivorous species and medium-to-large fruit-eating bats predominate.