At least 308 species or subspecies of stygo- or troglobionts and at least 735 species or subspecies of mostly presumed stygo- or troglophiles representing 17 phyla, 38 classes, 90 orders, and 278 families of invertebrates are currently known to populate the caves and subterranean waters of Russia and other countries of the former Soviet Union. The main evolutionary burst in the endogean habitats including the MSS (milieu souterrain superficiel, or mesovoid shallow stratum) is observed in arthropods, primarily crustaceans, collembolans, and beetles. The major centers of taxonomic diversity among stygo- and troglobionts within the study region are the Caucasus (181 species, or almost 59%) and Crimea (44 species, or over 14%), which are montane karstified "glacial" refugia of the nemoral biota. The contribution of the other major regions including karstified areas is considerably smaller and gradually decreases from Central Asia (35 species; over 11%), the Far East (33; nearly 11%), the Ukrainian Carpathians with Podolia (12; almost 4%), the Russian Plain (7; over 2%), the Urals and Ural region (7; over 2%) to Siberia (5 species; 1.6%). Inventorying remains a topical problem in assessing the stygo- and troglofaunas of the territories in question. The most complete bibliography possible is included.