The Stviga River represents a unique water object as it is the main waterway of the wildlife area of republican value “Olmanskiye bolota”. 72 types of hydrobionts, which fall into 3 types of water invertebrate animals, are revealed: Mollusca – 11; Annelida – 2, Arthropoda –59 species. Among the revealed water invertebrates, more than a third are new and are for the first time noted not only in the river Stviga, but also in general in reservoirs of the wildlife area “Olmanskiye bolota”. It indicates that the fauna of the water invertebrates living in the territory of the wildlife area “Olmanskiye bolota” remains still studied insufficiently. The revealed specific structure of the macrozoobenthos complex of the Stviga River is presented by the basic taxonomical groups of water invertebrate animals characteristic of the river ecosystems of Belarus. Rather high specific abundance of larvae from Plecoptera, Ephemeroptera and Trichoptera groups is noted. It indicates in general rather high quality of waters in the studied alignments of the Stviga River. Among the animals of macrozoobenthos representatives, it should be noted the find of the following rare species for Belarus – larvae Isoptena serricornis (Pictet, 1841) and Taeniopteryx nebulosa (Linnaeus, 1758) and also mollusc – Ferrissia fragilis (Tryon, 1863).