In the Republic of Kazakhstan a market economy, a democratic political system and a free civil society based on ideological, social and political pluralism are developing. This contributes to the development of constitutional norms and the diversity of new legal institutions that ensure the supremacy of the Constitution. These include the constitutional Council. In 2020, it's been twenty-five years from the date of adoption of the Constitution of the Republic of Kazakhstan and the creation of the constitutional Council of the Republic of Kazakhstan, ensuring the supremacy of the Constitution throughout the territory of the Republic. The constitutional Council of the Republic of Kazakhstan is not part of any of the three branches of government and is subject only to the Constitution of the Republic of Kazakhstan and the law. The purpose of this article is a comprehensive analysis of theoretical and practical issues of interaction between the constitutional Council of the Republic of Kazakhstan and other institutions of state power. In this regard, the article contains the results of the analysis of the foundations of the constitutional system of the Republic; constitutional supervision of the prosecutor's office; the institution, functions and instruments of power of the President, mechanisms of interaction of the Constitutional Council as a constitutional supervisory body with the President of the Republic of Kazakhstan, the Parliament of the Republic of Kazakhstan and the Government of the Republic of Kazakhstan. A comprehensive study of the activities of the constitutional Council of the Republic of Kazakhstan on the constitutionalization of current legislation is one of the current theoretical and practical problems. It is determined by the scale and quality of the current legislation adopted during the period of fundamental social reforms, the need to «correct» and improve it. In this regard, a significant role is assigned to the Constitutional Council, whose activities are subject to scientific analysis and reflection. In addition, the authors studied and revealed the line of interaction of the constitutional Council and other government institutions are considered in the areas of initiation of constitutional proceedings in the Council, organisational, legal, information procedures, determine the composition of the constitutional Council, overcoming the objections of the President to the constitutional Council's decision. The institutional method used in the article made it possible to show the essence and significance of the constitutional Council in the system of state authorities