We studied the status of toads of the genus Rhinella collected in the southern Cordillera Azul, central Peru. Molecular analysis of the mitochondrial 16S rRNA gene revealed them to be members of the recently proposed Rhinella festae species group, and sister to R. lilyrodriguezae, a species known from northern areas of the Cordillera Azul. The new specimens are differentiated from R. lilyrodriguezae and other species of Rhinella by substantial genetic divergence in the studied gene fragment (> 5% uncorrected pairwise distance) and several qualitative morphological characters, providing combined evidence for a divergent evolutionary lineage. We consequently describe the specimens from the southern part of the Cordillera Azul in Departamento Huánuco as a new species, Rhinella chullachaki sp. n. We briefly discuss the definition and content of species groups in Rhinella as well as the difficulties hampering taxonomic resolution within this species-rich genus.