The algoflora of water bodies play an important role in maintaining the ecological balance in water ecosystems, they are the primary producers of organic matter, which present the nutritional basis of the trophic chains in these ecosystems, and the assimilation of compounds from the water environment ensures the process of self-purification of water bodies. Due to the bioindicator capacity of many algae species, algoflora represents an important component in the bioecological monitoring system of water bodies. The planktonic algoflora in the water of the Răut River in the sectors located within the limits of the Bălți and Florești urban ecosystems was studied based on the planktonic samples taken in 10 stations established along the river, its tributaries, lakes on the territory of the Bălți urboecosystem and 2 stations established along the course of the river upstream and downstream of the waste water treatment station in the Floreşti urban ecosystem during the year 2019-2022. Temperature, transparency, pH and chemical analysis of the water were measured in the studied sites. The planktonic algae flora in the studied stations is represented by 141 species and 4 varieties of algae, from the phyla: Cyanophyta – 14 species, Chlorophyta – 47 species, Chrysophyta – 13 species, Bacillariophyta 46 species and 4 var., Pyrrophyta – 2 species, Euglenophyta -19 species and 1 var. The two major groups according to diversity, Chlorophyta and Bacillariophyta form the dominant complexes in most of the investigated stations, but in the sites where the river water has a high degree of eutrophication, for example, the Răut river upstream and downstream of the wastewater treatment stations in the Bălți and Floreşti city, in the water of the river upstream and downstream of the place of confluence with the Copăceanca tributary, the dominant complexes are formed by representatives of the phyla Euglenophyta and Cyanophyta. Fluctuations in the taxonomic structure of the planktonic algal flora, which manifest both seasonally and during the period of our investigations, are explained by the instability of environmental factors, the anthropogenic impact, which is quite pronounced throughout the water area of the Răut River, but especially the course of the river located within the urboecosystems and the adjacent sectors.