The external morphology, oral cavity, chondrocranium and hyobranchial skeleton of Telmatobius atahualpai larvae are described. These tadpoles present an oral disc modified into a sucker apparatus and were originally assigned to Hyloscirtus. In order to justify its taxonomic position in Telmatobius, we compare its morphology with Hyloscirtus armatus, H. phyllognathus, Telmatobius truebae, and published data on larvae of other Hyloscirtus and Telmatobius. Tadpoles of T. atahualpai and other Telmatobius differ from the examined species of Hyloscirtus in having a transangular oral disc, inner wall of spiracle present as a slight ridge, two pairs of infralabial projections, smooth prenarial arena, one papilla between postnarial papillae and median ridge, buccal roof arena defined by papillae which converge posteriorly, cornua trabeculae neither expanded anteriorly nor fused medially, syndesmotic articulation between suprarrostral and cornua trabeculae, maximum width of chondrocranium only at the level of the arcus subocularis, fenestrae parietales open, tip of the processus posterior hyalis does not underlie the anterolateral part of the hypobranchial plate, processus posterior hyalis and hypobranchial plate attached only by a ligament, and commissura proximalis III absent. The tadpole of T. atahualpai is different from other reophilous Telmatobius larvae in having a oral disc completely bordered by marginal papillae and a labial tooth row formula of 3/7(1). T. atahualpai larvae seem to represent the most specialized Telmatobius tadpole known so far.