For the first time, a freshwater prawn of the genus Macrobrachium Spence Bate, 1868, earlier unknown for the basin of the Azov Sea, was recorded in the lower reaches of the Don River in September, 2019. Based on their morphological characteristics, the found specimens were identified as M. nipponense (De Haan, 1849). This work presents the results of genetic analysis confirming the species status of the prawn, and also reports on new discovery and spreading of this species in the Don River. Oriental river prawn M. nipponense is a subtropical species, in its natural range widespread in Southeast Asia. Since the middle of the 1960s, this species is rapidly expanding its range in Eurasia. In a temperate climatic zone within the area of the former USSR, this thermophilic species was introduced in cooling ponds of thermal power plants (TPP). Acclimatization of M. nipponense was carried out as a part of warm-water aquaculture in order to improve the food supply of fish and enrich the fauna of TPP cooling ponds. This paper summarizes the available information about the formation of stable populations of M. nipponense within the area of the former USSR countries, as well as an assessment of the risks of invasion in the Don River.