The relationship model between Head of the State and the executive branch largely determines the essence of the form of government. Each republican form of government establishes its own intrinsic way of the President – the executive branch relationship. In modern republics, considerable differences can be seen both in the way the President is connected to the executive branch, and in the extent of such connection. The arrangement of State power in republics with presidential and parliamentary forms of government embodies two alternative ways of the President - the executive branch relationship. While in the presidential republic the President is connected to the executive branch structurally and heads the system of its bodies, in the parliamentary republic the President is distanced from the executive branch to the fullest possible extent. In a mixed republic, the President is beyond the executive branch structurally but is significantly integrated into it functionally. Different ways in which the President and the executive branch are related rest upon different doctrinal approaches to the understanding of the functional nature of the President and the President’s role in the State mechanism. The search for an optimal structural and functional relationship between the President and the executive branch has always been the keynote in the entire history of development of the republican form of government. The results of this search are manifested in the diversity of modern republics. However, even today the President – the executive branch relationship remains the issue in the focus of scientific debates. The accumulated experience of the republican State-building demonstrates that both the structural merger of the President with the executive branch and the maximum distance between these institutions limit the functional potential of Head of the State and engender executive power concentration in the hands of a single person. The relationship of the President and the executive branch becomes a particularly critical issue in the post-Soviet republics, where the intention to enhance the executive branch’s efficiency by increasing the President’s influence on it was in many cases implemented very carelessly. In most post-Soviet republics, at least at the initial stage of their development, enhancement of the constitutional status of the President reached a critical limit making the system of executive authorities administratively subordinated to the President. This eventually distorted the nature of the mixed republican form of government used in these republics and became one of the most important causes triggering the development of the superpresidency phenomenon. The relationship of the President of Ukraine with the executive branch is a key issue for determining the prospects of the constitutional correction of the national form of government. Across the full range of contexts, any type of connection of the President of Ukraine and the executive branch should neither interfere with the constitutional functions of Head of the State, nor turn the latter into an actual head of the executive branch.