Abstract: The research object is the problems of preserving state sovereignty in the era of globalization. The problem of understanding the very concept of “state sovereignty” as a constitutional and legal category is still topical. Urgent is the problem of preservation and indivisibility of state sovereignty of a state when it joins an interstate association and delegates state powers to the supranational body of this association. This problem is especially topical for the Russian Federation since the country is a participant of the Eurasian Economic Union. The research methodology is based on the dialectical approach considering phenomena and processes in their dialectical interrelation, contradictions and development. The author uses general scientific methods (analysis, synthesis, induction, deduction, classification, description and comparison) and specific scientific methods (formal-legal, comparative-legal, historical-legal and system-structural). The scientific novelty of the study consists in the detection of essential components of state sovereignty. The author defines the peculiarities of the Eurasian Economic Union as an interstate association, analyzes the problem of obligatory and non-obligatory nature of decisions of the bodies of the Union for its member-states. The author formulates the conclusion that when Russia joins an interstate association, the principle of preserving the state sovereignty comes into action, since joining an interstate association is connected with free-will delegation of state powers by the state to the supranational association in a particular sphere for the purpose of national interests.