We describe a new species of Atelopus from the Amazonian slopes of the Cordillera Oriental in southern Peru. The new species is superficially similar to the northern Peruvian species A. pulcher and A. spumarius, but molecular markers place it in a different clade. In addition, it lacks a middle ear and has its dorsal skin covered with minute coni. The putative distribution of the new species includes the Andean piedmont in the departments of Cusco, Madre de Dios and Puno, encompassing an area of approximately 400 km in length and an altitudinal range of 400-1,000 m above sea level. © 2011 Deutsche Gesellschaft für Herpetologie und Terrarienkunde e.V. (DGHT), Rheinbach, Germany.