The main objective of this article is to systematize the knowledge of the place occupied, and the role played, in the structure of government administration by the head of the Internal Security Agency. The author examines legal solutions allowing to characterize the legal status of the head of the Internal Security Agency as a body performing tasks arising from the functions of the State and as the entity in charge of a part of government administration capable to perform these tasks. According to the author, this objective requires presentation of the constitutional and statutory provisions relating to the position of Head of the Internal Security Agency and characterization of powers which he/she may use in order to implement his/her tasks. The article provides a survey of the constitutional solutions that determine the status of the Head of the Internal Security Agency as central government administration body. In this context, the author shows the relations between the Head of the Internal Security Agency and the Prime Minister, to whom he/she is subordinate and who oversees the activities of the Internal Security Agency. He also provides an analysis of the principles of organization and management of the substantive work of the Agency. From this analysis it clearly follows that the Head of the Agency has to play at least some of the key roles in the “governmental” system of the State security. On the one hand, it accounts for an important aspect of national security, which is the “internal security” and “protection of the constitutional order”. On the other hand, the head of the Internal Security Agency has the authority to initiate certain specifi c activities of the Agency in fulfi llment of its tasks. His/her scope of competences include also assessment of performance of the Agency’s functionaries in the context of their offi cial operations. Moreover, he/she is responsible for implementation of important duties in rendering information to constitutional organs of the executive and to parliament.