The article presents the results of studies of zooplankton and macrozoobenthos of small reservoirs on the territory of the State Natural Reserve «Kologrivsky Les» named after M.G. Sinitsyn. The hydrochemical and hydrophysical parameters of small reservoirs are given. In summer, the highest biomass and abundance of zooplankton were observed for long-existing beaver ponds on streams. In autumn, among the studied small reservoirs, the highest biomass and abundance of zooplankton are characteristic of oxbow lakes. The highest biomass of benthos was noted in oxbow lakes, and its abundance was found in beaver ponds. An analysis of the ecological groups of zooplankton and benthos by type of nutrition was carried out. In autumn, the composition of zooplankton was marked by a predominance of vertical feeders and primary filter feeders in beaver ponds, primary filter feeders and predatory forms in ditches, primary filter feeders and vertical feeders in oxbow lakes, and secondary filter feeders, scrapers, detritivores and stand feeders in hollows in wetlands. The benthos of beaver ponds and oxbow lakes contains all six ecological groups of benthos based on feeding type. There are no collectors, obligate filter feeders or active predators in the ditches. Only soil ingesters were noted in the hollows. A number of indices have been calculated to characterize the structure of zooplankton.