The article examines the current constitutional and legal problems of the formation and implementation of the control activities of ombudsman in the modern world. It is proved that the history of development, the causes, the processes of institutionalization and constitution of Ombudsman services in the modern world, the permanent transformation of their functions and the differentiation of their specialization are evidence of the improvement of the classical system of separation of powers. Following the legal traditions of democratic countries, the Institute of the Ukrainian Parliament Commissioner for Human Rights was introduced in Ukraine. Today, it has become an important way of ensuring human rights. The introduction of the Institute of the Ukrainian Parliament Commissioner for Human Rights fully meets the current trends in the modern democratic world and is a reflection on those systemic challenges and complex problems that exist in the field of human rights protection. The article argues that the social tension and insecurity of certain segments of the population, in particular children, pensioners, persons with disabilities, servicemen, migrants, internally displaced persons, ethnic minorities, persons belonging to the LGBTI community, entrepreneurs, patients and other categories of the community , demonstrates the need to improve national mechanisms and forms of human rights protection, including strengthening the oversight functions of the Ukrainian Parliament Commissioner for Human Rights. It is argued that the functional isolation, independence and organizational diversity of control bodies, primarily ombudsman, is evidence of the formation of control power, the conceptual idea of which is the existence of a system of organizational, regulatory, institutional measures to ensure control over public authority. It is concluded that fundamental constitutional values, among which, first of all, human rights and the authority responsible to him are the functional and teleological dominant activity of the Ombudsman, the feasibility of creating and the practice of functioning of which, in fact, is due to the solution of these interrelated tasks. According to the author, in order to improve the Ombudsman Institute in Ukraine, it is advisable to continue the constitutional and project work on amendments to the Constitution of Ukraine, which provide for the possibility of introducing specialized parliamentary ombudsmen (on issues of the child, servicemen, equal opportunities, national minorities, etc.) the scope of their control activities.