Communication by acoustic signals has been extensively studied in anuran amphibians, but other sensory modalities have been largely ignored. We show here that the frog Leiopelma hamiltoni communicates through fecal chemosignals. When given a choice between their own and other individuals' feces, subjects spent more time near their own feces. Further, this effect was greatest when the conspecific was larger in body size, suggesting that information about size as well as individuality is communicated. Time spent near conspecific feces correlated negatively with the distance between the collection sites of the frogs. This correlation may reflect differential responses to the feces of frogs of varied levels of kinship and social familiarity: frogs may avoid nonrelatives and unfamiliar conspecifics. To test the hypothesis that frogs alter fecal production upon exposure to conspecific feces, we presented subjects with either one smear of their own and one smear of a conspecific's feces or two smears of their own feces. Frogs did not defecate more when exposed to conspecific feces. However, when the frogs did defecate, they placed their feces closer to the conspecific's feces than to their own. This supports our hypothesis that feces serve as signals to conspecifics. Visual and tactile cues were eliminated in our experiments. Our results show that the frog L. hamiltoni communicates with conspecifics through chemical signals. We suggest that chemical signaling may be widespread in anuran amphibians.