ENThe article analyzes the current state of the study of Blue Waters Battle. The researcher analyzed data of sources, as well as the Ukrainian, the Lithuanian and the Polish historiography. The author concludes that the most important outcome of the Battle of Blue Waters was a section between Olgerd and Mamay of the Ak-Orda territory and creation of Mamay Horde in the Azov steppes. The incorporation of Podolia and the Southern Rus by the Grand Duchy of Lithuania has turned it into one of the largest countries of the Central- Eastern Europe.