The article substantiates the interrelation of the non-positivistic legal system based on consideration of the inherent in the law aspiration to justice, with the necessity of highlighting the principle of balance of public and private interests. The results of the main comprehensive scientific research in the fi eld that are based on the consideration of public and private interests balance as a basic legal idea as well as the necessity of its implementation in constitutional and international justice are highlighted. The author concluded that there is constitutional and legal basis for distinguishing the balance of public and private interests as a general legal principle, as well as general approaches to its content in both legal theory and sectoral legal sciences. In order to eliminate the difference in terminology used (balance of interests, ratability, proportionality, balance of constitutional values), it is proposed to use the phrase «balance of public and private interests». In the author’s view, the use of such terminology underlines that the principle under consideration is primarily addressed to the legislator and allows to focus on the objectives for the achievement of which legal regulation is established in certain areas of public relations. Other terms are used mostly in relation to the implementation of this principle in constitutional justice. The dualistic principle to determine the content of the principle of balancing public and private interests is proposed. Firstly, the principle under consideration is about the duty of the legislator and the court to use the necessary and sufficient means to ensure a fair relationship between different interests in establishing legal regulation and resolving disputes. The second approach has instrumental significance and is related to the implementation of this principle within the framework of constitutional proceedings on the basis of proportionality and balance of constitutional values.