The genus Adenomera has been a difficult group for systematic studies because the species are similar and geographically variable. Two species have been reported from the Peruvian Amazon Basin: Adenomera andreae and Adenomera hylaedactyla. However, acoustic recordings from the Tambopata National Reserve in southeastern Peru reveal four sympatric advertisement call types that are distinctive in acoustic parameters and to the human ear. Some subtle morphological differences are also present. We conclude that there are at least four sympatric species at Tambopata and that Adenomera has a greater species diversity than currently acknowledged.