The diet of Noctilio leporinus was examined on the Island of Culebra, Puerto Rico, by collecting discarded prey below roosts and by making biweekly collections of guano over a 9-month period. Small insects, mostly beetles and moths, predominated in the diet during the wet season. During the dry season, pelagic and freshwater fish represented a greater proportion of the diet than did insects. Crabs, scorpions, shrimp, and terrestrial insects were consumed in small quantities. Small beetles, moths, and other insects were caught in flight, whereas fish and terrestrial invertebrates were caught in a bats' feet. N. leporinus is both an aerial insectivore and piscivore, with a flexible foraging strategy that can adjust to local conditions and include terrestrial prey.