Within the framework of this article, the author identifies a special group of private law institutions based on the presence of a special element in them – public legal interest. The author notes that private and public interests are in close interaction, and the number of legal structures arranged according to this principle seems to be quite large. In this regard, the author studies private law institutions that participate in ensuring national security as an example of the implementation of public interest. In the course of the work, the author refers to the National Security Strategy of the Russian Federation, and also defines national security, provides an approximate list of objects of its protection, defining the role of private law institutions in ensuring national security. According to the author's conclusion, the state of almost all private law institutions directly or indirectly affects the provision of national security, however, private law institutions play the greatest role, on the basis of which the key needs of the state are met, as well as civil society institutions. Based on the results of the article, the state of legislation concerning the role of private law institutions in ensuring national security is highly appreciated, however, according to the author, some of its aspects are subject to addition or reform.