Pachyseius accedens sp. nov. and Pachyseius arrhenobasis sp. nov. are described and illustrated based on specimens from litter and soil detritus of montane forest habitats in Bulgaria (Rhodope Mts., Malesh Mts.) and Romania (Carpathian Mts.: Bargau Mts., Calimani Mts.), respectively. In addition, Pachyseius angustiventris Willmann, 1935, a little known and inadequately described congeneric species, is newly redescribed and illustrated, based on females from the Western and Central Europe (Wales, Germany). Comparing the type material of the following species, Pachyseius morenoi Moraza, 1993 is not considered to be a valid species, and is included in synonymy with P. angustiventris.