With the passing of the Code of Administrative Judicial Procedure of Ukraine, the constitutional regulation on the state’s responsibility for its actions (Art. 3 of the Constitution of Ukraine) started to be implemented by special judiciary organs (administrative courts) in public legal disputes. Thus, Ukrainian citizens have been granted qualified protection of rights, freedoms and legal interests of natural persons, and protection of rights and legal interests of legal persons, against offences by organs of state and local government, as well as of representatives of those organs and other subjects, in connections with the carrying out of their administrative functions on the basis of legislative acts, including those connected with the exercising of delegated powers (article 2 part 1 of the Code of Administrative Judicial Procedure). The introduction of a competent institution of administrative judiciary has been conditioned by pro-European orientation of Ukraine, whose development as a modern and law-abiding country is still progressing.Thus, Ukraine has witnessed changes and amendments being introduced to administrative procedural legislation and science, with brand-new notions and categories appearing, e.g. ‘the subject of authority’s powers’. The notion refers to organs of state and local government, as well as to their officials and workers. In his article, the author analyses the problems of legal regulations concerning liability of the subjects in administrative proceedings, and of their exercising legal subjectivity as regards administrative procedures. Based on the analysis of the legal regulations in force, the author concludes that the Code of Administrative Judicial Procedure of Ukraine and other normative and legal acts need to be improved.