The aim was to study the main qualitative and quantitative characteristics of phytoplankton in the studied areas of surface water bodies of the Bukhara region. It was found that in the studied water bodies (Tudakul lakes and Kuyumazar reservoir), Bacillariophyta (34 species), Chlorophyta (20 species), Cyanophyta(15 species), less often Dinophyta(5 species), Englenophyta (1 species) were found. The highest total phytoplankton abundance in water samples from both reservoirs was Cyanophyta, and the highest phytoplankton biomass was recorded in Bacillariophyta and Chlorophyta. At the same time, Englenophyta and Dinophyta were not found in the waters of the Kuyumazarreservoir. In the phytoplankton samples from Lake Tudakul, planktonic freshwater-brackish-water forms bmesosaprobic predominated; brackish-water b- and b- and α-mesosaprobic species of algae prevailed. The role of aquatic organisms in the life of various water bodies is enormous. They take part in the circulation of matter and energy, in the accumulation of bottom sediments, and are also of great medical and social importance due to the use of numerous surface water bodies for household, drinking and cultural and domestic purposes [1, 3]. For this reason, the determination of phytoplankton is mandatory according to UzSS 950-2011 “Drinking water. Hygiene requirements and quality control “(Interstate Standard) and UzSS 951-2011” Sources of centralized drinking water supply.Hygienic, technical requirements and selection rules” (Interstate Standard) [12, 13] The most important part of aquatic ecosystems is the aquatic biota, represented by a mosaic of interconnected biocenoses that occupy all possible biotopes in watercourses and reservoirs: they inhabit the water column (plankton), the thickness and surface of the soil (benthos), overgrow the surface of solid rocky substrates washed by water or settling on the surface of macrophytes and in the turf of water moss (periphyton). Their species composition and structure are entirely determined by the climatic and landscape conditions prevailing in the river corridors and coastal zones of lakes [2]. Consequently, biocenoses can be considered as information systems that characterize the state of not only specific water bodies, but also the surrounding natural complexes on the territory of which they are located [8]. Byuniting into communities, the residence time of living beings (bacteria, zoobenthos) in the water may be lengthened, and therefore it was advisable to study hydrobiological parameters together with microbiological indicators [3]