We describe a new species of Pristimantis from high Andean grasslands (jalca) at 3600 m above sea level in northern Peru (Región Cajamarca) based on morphological and molecular characters. The new species is known from four males and five females, which were found sheltering in the rosettes of Puya fastuosa (Bromeliaceae). The phylogenetic analysis of a fragment of the mitochondrial 16S rRNA gene suggests that the new species is a sister taxon of Pristimantis simonsii. The new species differs from its congeners by having a black dorsum speckled with white flecks and a dark brown groin with white spots. Furthermore, adult males have a snout–vent length of 23.6–27.2 mm (n = 4), and adult females of 25.6–32.8 mm (n = 5). Intensive mining activities apparently have extirpated the new species at its type locality and it is therefore considered critically endangered. We discuss the impact of mining on biodiversity and biological surveys in Peru.