A new species of Catamicrophyllum Verhoeff, 1901, Catamicrophyllum beroni sp. nov., is described from Rila Mts, southwest Bulgaria. The new species is compared to its most similar congener, Catamicrophyllum caucasicum (Attems, 1901) known from the Caucasus and Eastern Anatolia, including descriptive notes and scanning electron micrographs of the latter. The remarkably disjunct distribution areas of the two species are briefly discussed in the context of similar distribution patterns in other members of Julidae. In addition, some ecological notes and conservation issues in connection with the climatic changes occurring in the area of the type locality of C. beroni sp. nov. are presented.