Female treefrogs (Hyla cinerea andH. gratiosa) can accurately localize a sound source (playback of male mating calls) if both ears are intact. When the sensitivity of one eardrum is attenuated, by coating it with a thin layer of silicone grease, females no longer can locate the sound source. This study demonstrates that female anurans rely on interaural cues for localization of a calling male. The neural basis for an anuran's sound localization ability presumably involves binaural convergence on single cells in the central auditory nervous system.