We evaluated partitioning of food resources among syntopic eastern red (Lasiurus borealis), Seminole (L. seminolus) and evening (Nycticeius humeralis) bats at the Savannah River Site, South Carolina, from June through August of 1996 and 1997. We compared diets to indices of relative prey availability, which were based on samples of the insect communities in bat foraging habitats and the amounts of time the bats foraged in each habitat. The relative proportions of insect orders consumed differed among the species. We recorded only minor differences between insect consumption and indices of prey availability, as assessed by insect light traps placed within foraging habitats. Our data suggest that Eastern red bats and evening bats altered their prey selection late in the summer.