In the present work are revealed the results of the multi-annual researches on the ecological situation in Dniester river. The building of hydropower stations in Ukraine (HPS-1, HPS-2 and HAPS) constructions on the Dniester river have negative impact on the river ecosystems: • impairment of river hydrological regime; • the river is covering with water plants; • impairment of natural dynamics and processes of migration of chemical elements in the system «water-suspended matter-sediments»; • the processes of secondary pollution of water were intensifi ed;. • the riverine species of hydrobionts are replaced with lacustric species;.