The article refers to the participation of the illustrious Romanian diplomat Nicolae Titulescu in the works of the Paris Peace Conference (1919-1920), in the elaboration of the Treaties signed by Romania, including – the Treaty on Romania’s Sovereignty over Bessarabia, signed on October 28, 1920 by Romania with France, Great Britain, Italy and Japan. Being in the position of Minister of Foreign Affairs, N. Titulescu pleaded for the recognition and inviolability of the border on the Dniester with the USSR. He managed to impose his point of view in a series of international treaties in which Romania and the USSR were part, but also in the Soviet-Romanian Agreement of Mutual Assistance, initialed by N. Titulescu and M. Litvinov, Soviet People’s Commissar for Foreign Affairs. At the beginning of 1940, N. Titulescu sent King Carol II a Memorandum on the history of Romanian-Soviet relations and expounded Romania’s arguments regarding its sovereignty over Bessarabia.