Abstract
In the world over the past half century, more than 500 international conflicts have taken place regarding transboundary water resources. Problems of using transboundary water resources were a source of disagreement during attempts at uncoordinated construction of water bodies and the transfer of pollution. The article discusses the instruments of international law in the field of protection of inland waters and rivers. Inland water law is one of the oldest parts of international environmental law. The first rules containing elements of regulation of environmental problems arose already in the 18th century and mainly concerned the use and protection of navigable rivers. The article shows the dynamics of the development of international law relating to transboundary waters in Europe, pays attention to the fundamental documents regulating water relations in the field of protection of transboundary rivers, and also examines the role of international organizations as instruments of international environmental law in the field of protection of transboundary waters.