Moths are the primary prey of the Ozark big-eared bat (Corynorhinus townsendii ingens), but it is unclear how this prey base varies over the landscape. We investigated moth occurrence around roosts of this federally endangered bat and examined its diet. In 2005, lepidopteran assemblages were sampled via light traps in habitats near roost sites in both an agriculturally-fragmented and forested landscape in the Ozark Mountains of Arkansas. Moths (wingspan > 20 mm) were identified to the lowest taxon possible and enumerated, yielding 8,720 moths consisting of ≥ 314 species in 22 families. Habitat selection was analyzed for common families (n > 100 specimens) in each landscape. Edge habitat was generally avoided in the fragmented landscape, and moth occurrence in riparian and upland forest varied among prey families (P < 0.01). In the forested landscape, prey were found in older, larger size-classes of timber; sapling timber was generally avoided (P < 0.01). Moth wings discarded by the Ozark big-eared bat while feeding were collected from roosts to assess prey consumption. Noctuidae and Notodontidae were consistently consumed in both landscapes, but consumption of other taxa varied. Geometridae and, to a lesser extent, Arctiidae were consumed in the fragmented landscape, but generally not in the forested landscape. In contrast, Sphingidae were a substantial portion of the diet in the forested landscape, but were not consumed in the fragmented landscape. Differential prey consumption may reflect differences in land use or habitat availability between landscapes.