A new arboreal species of Rhinella is described from the humid montane forest of Manu National Park in the Cordillera Oriental of southern Peru. The new species can be distinguished from all known Rhinella by a unique combination of external and osteological characters as well as by molecular data. The new toad is compared to R. arborescandens and R. veraguensis with respect to external characters. On the basis of morphological and molecular data, the new taxon is closely related to R. chavin, R. nesiotes, and R. festae. Although DNA data indicate that a member of the R. veraguensis group (R. nesiotes) is its sister taxon, the new species is not closely related to other members of this species group (e.g., R. veraguensis). In addition, DNA data indicate that the R. veraguensis group as it currently is defined is paraphyletic. Until additional studies are completed on the phylogeny of these South American toads, we refrain from assigning the new taxon to a species group. © 2007 by The Herpetologists' League, Inc.