The paper presents a reassessment of some pieces of evidence on Assyro-Babylonian struggle for the Middle Euphrates valley (Mari, Hana, Rapiqu) in the 13th c. BC. The author comes to the following conclusions: under Kadashman-Turgu the Middle Euphrates valley was still under Babylonian control (which presumably still existed at the moment of Kadashman-Ellil II’s accession), thereafter it was conquered by Adadnerari I (in the course of a campaign not reflected in «Synchronistic History») and was not controlled by Babylonians at the moment when KBo I 10 was sent. However, later the valley was reconquered by Babylonians (presumably in the frame of some conflict with Shalmaneser, probably referred to in Tukulti-Ninurta Epic) and returned to Assyria due to Tukulti-Ninurta’s conquest of Babylon.