Typhlochactas sissomi, a new species of troglomorphic scorpion in the subfamily Typhlochactinae Mitchell, 1971, is described, based on a single subadult male collected under a stone in a mesophilous forest in the mountains of the state of Queretaro, Mexico. This is the seventh species in the genus Typhlochactas Mitchell, 1971. Although all seven species are troglomorphic, four are troglobitic and two are humicolous. The new species described here is probably also humicolous. A key to the identification of Typhlochactas species is presented.