Introduction: in the paper, the author aims to analyze the content and legal significance of the international legal principles of environmental protection in the context of the prospects for the formation of an international environmental organization in the Caspian region. The author focuses on the principles that have already been enshrined in the international legal treaties concluded by the Caspian Sea States: the precautionary approach, the “polluter pays” principle, the principle of accessibility of information on marine pollution, and the principle of the ecosystem approach. Methods: the methodological framework for the study is the methods of analysis and synthesis, the empirical methods of comparison, interpretation, as well as such specific scientific methods as the legaldogmatic method and the method of interpretation of legal norms. Results: the results of the study show that the development of the regional environmental protection institutions in the Caspian region should take into account the international legal principles of environmental protection. In particular, based on the analysis of the abovementioned international legal principles, the author justifies the need to give a possible regional interstate environmental organization the functions of monitoring, tracking the causes of harm, the function of a center for collecting, processing and distributing information, as well as coordinating the activities of all existing international and national structures to improve the efficiency of their cooperation. Discussion and conclusions: the development of the regional environmental institutions is impossible without taking into account the international legal principles enshrined in the regional international treaties. The author concludes that it is necessary to apply the content of such principles in the formation of a regional interstate environmental organization.