AbstractZoobenthos communities had been studied in the middle and lower parts of the Boguchany reservoir for five years (2014-2015, 2017-2019). The benthic fauna was chironomid-gammarid in nature with a predominance of chironomids. The littoral communities are qualitatively and quantitatively much richer than in the profundal. With a decrease in depth, there was an increase in the number of invertebrates by about 6 times due to the small-sized species of chironomids. The trophic status of the Boguchany reservoir in 2018 corresponded to the mesotrophic type of medium food capacity (III class), in other years - to the oligotrophic type of low food capacity (II class). Currently, the formation of bottom fauna is at the stage of biocenosis stabilization. An integrated approach was used to assess water quality according to bottom communities. The fundamental criterion for the selection of indices was the consideration of the benthocenosis structural organization, i.e. the development degree of indicator taxa. Water quality, assessed by the state of zoobenthos communities, corresponded to III class, “Moderately polluted”, β-mesosaprobic zone.