Abstract: Institutional approach in the study of administrative law annually requires particular novations due to the changes in the legislation and appearance of new research subjects. The authors of the article attempt to convince the colleagues of the necessity to consider the problem of including the institution of declaring in the course of administrative law. Declaring as an administrative institution had been forming in Russia sequentially during a long period of time, but has experienced qualitative changes only recently. Today it may safely be said that the institution of declaring has finally overcome the limits of the common intersectoral institution of tax and customs law, has acquired the qualities and features characterizing it as an independent administrative-legal institution. In the context of intensive development and updating of the legal matter of administrative law, the new forms and methods of legal research appear, certain administrative-legal institutions transform, thus acquiring a new role in the system of institutions of administrative law. Administrative legal institution of declaring is a set of administrative legal provisions, regulating social relations, appearing after informing of the authorities by physical and legal persons, in accordance with the procedure established by law, about their incomes, the incomes of third parties, about the correspondence of funds, possessions, and other material objects, belonging to them, or goods or services, produced by them, to the regulatory qualitative or (and) quantitative indexes, for the purpose of the intraeconomic and state control (supervision) in the fields of activity, defined by administrative legislation.