Abstract: The study of snails (family Valvatidae) of water bodies in the “Vitimskiy” State Nature Reserve and adjacent areas (Eastern Siberia) is relevant due to the insufficient knowledge of the malacofauna and the transient zoogeographical position of the Vitim River basin, as well as the negative impacts of active mining on aquatic ecosystems. The purpose of this article is to characterize the species content and distribution of valvatid snails in the study area in connection with the main environmental factors. Having analyzed our collections from the studied area in 2019 and 2020, we have identified six species of the genus Valvata. An annotated list of species, with their zoogeographical characteristics, shell images, measurements, and morphometric indices, and a key for identifying valvatid snails of the Reserve and adjacent areas are provided. Based on a complete set of data on the occurrence of freshwater mollusks in 207 habitats, a matrix of occurrence of valvatids is prepared; the use of various statistical algorithms has made it possible to determine the completeness of identification and features of the distribution of species richness of mollusks, perform the classification and ordination of habitats and species associated with them, and identify differences in the distribution of species caused by environmental factors. The impact of taxonomical uncertainty on the progress of knowledge about ecology of valvatid snails is discussed.