Habitat degradation and loss threaten the survival of many bat species. Recent studies in Madagascar however have found some species are present in areas of low forest cover even though their echolocation calls and wing morphology suggest they are able to forage in forests. The present study investigated habitat use and prey selection in two sympatric hipposiderid bats, Triaenops furculus and T. menamena, in the dry southwest of Madagascar. The study colony occupied a cave in limestone karst surrounded by intact spiny bush and several secondary or degraded habitats. We used bat detectors and radiotracking to determine habitat use, and faecal analysis and invertebrate sampling to assess prey selection. Spiny bush, the dominant habitat type in the study area, was used less than predicted from its availability, based on satellite imagery and ground-based habitat mapping. Areas containing large trees were used by radiotracked bats in approximate proportion to their availability and acoustic sampling revealed highest bat activity in this habitat. The radio-tracked individuals used agricultural land more than expected from its availability. A significant difference was found in the proportion of Lepidoptera in the faeces of the two species, with T. furculus showing a preference for moths. Triaenops furculus also selected Coleoptera, whereas T. menamena preferred mainly Hemiptera. While this study did not identify a strong association with forested habitats in T. furculus or T. menamena, it remains to be established whether the bats forage in a sub-optimal habitat due to their preference for roosting in the nearby karst caves.