The main objective of this study was to determine the composition and structure of freshwater snail communities of the Ruda River. The field research was conducted through the year at two different locations. The first location was the source of the river, and the second one was 250 m downstream. Quantitative samples of macroinvertebrates were collected on three different substrates (microhabitats) at each of two locations. Snails were separated from the benthos in the laboratory and were determined to the species level. Abundance of each species was determined based on the number of individuals, and age structure was based on morphometric measurements of their shells. During this study, a total of six snail species was found. Greater abundance was found at the source of the river, while communities were more diverse at the downstream location, especially on moss. The dominant species on the source of the river was Ancylus fluviatilis, while at downstream location the most common species was Horatia klecakiana. Analysis of the age structure of A. fluviatilis indicated that spawning occurs in spring and early summer while in species H. klecakiana occurs even twice a year, during mid-summer and late fall. The analysis of the functional feeding guilds showed that at the source grazers were present in greater numbers than detritivores which made less than 3 % of all snails. At the downstream location grazers were also dominant, but proportion of detritivores was higher, and shredders were also present. The obtained data are important contribution to the better knowledge on the freshwater snail fauna of the Ruda River.