The issues related to transboundary reservoirs in the state border zone of the Russian Federation and the Republic of Kazakhstan are analysed and their typology is articulated. Issues concerning the legal definition of the concept of "transboundary water body" in the legislation of the two countries are outlined. As a result of comparative decoding of differenttime images of remote satellite sensing of the earth, border sections where the course of rivers change were identified.Aim. To analyse and classify transboundary water bodies on sections of the state border of Russia and the Republic of Kazakhstan and identify problematic situations.Material and Methods. The study of these transboundary water bodies was carried out on the basis of both the analysis of interstate agreements on the delineation of the border of the Russian Federation and the Republic of Kazakhstan, the use of cartographic methods and the analysis of retrospective satellite images.Results. Inconsistencies in the level of legal definition of the concept of "transboundary water body" in the legislation of the two countries are shown. Transboundary water bodies on the state border of the Russian Federation and the Republic of Kazakhstan have been identified and classified. Based on a retrospective analysis of satellite images, problematic situations arising from changes in the location of water bodies as a result of channel deformations of transboundary rivers and fluctuation of lakes have been identified.Conclusions. According to the results of this work, all waterbodies located in the state border zone along its entire length have been identified. A typology of these has been carried out and the length of boundary watercourse sections has been established. Using the example of the transborder Ural River, the situation of the section of the river along which the state border lies is shown with an analysis of the changes in the channel and their dynamics.