Troglotayosicus hirsutus, a new species of troglomorphic scorpion, is described based on three adult males, three adult females and eight juveniles captured by ultraviolet light detection in forest leaf litter of the municipality of Buesaco, south-western Colombia. Though similar to the other Colombian species in the genus, Troglotayosicus humiculum Botero-Tru-jillo & Francke, 2009, T. hirsutus sp. nov. exhibits a combination of distinctive morphological features, including a densely hairy appearance which gives the name to the new species. With this description, the number of known species in the genus Troglotayosicus is raised to three, two of which inhabit leaf litter in forests of Nariño department (Colombia), whereas the type species, Troglotayosicus vachoni Lourenço, 1981, remains known only from Los Tayos Cave in Ecuador. With this new finding, it is plausible that the genus Troglotayosicus is not much rare after all, but that its apparent rarity might be a sampling artifact instead. However, this possibility does not imply that the genus is necessarily common, and only additional studies may tell about the vulnerability of the genus. Copyright © 2012 · Magnolia Press.