The paper is devoted to the consideration of issues related to the unification of financial law norms, which govern public relations on the internal distribution and redistribution of budgetary funds, into a single independent legal institution of financial law within its main sub-branch, namely budget law. The system patterns of law inherent in financial law and its structural elements became the conceptual basis of the research. It is established that the norms regulating the activities of public legal entities of the Russian Federation on budget regulation represent an independent complex financial and legal community and are a separate part of budget law. In the course of the study, various factors that determine the formation of a complex legal institution of budget regulation are identified. The author considers and formulates general and special principles of functioning of this legal institution, studies the main sources containing relevant financial and legal norms, analyses the structure of the legal institution of budget regulation and single out its sub-institutions. It is determined that the legal institution of budget regulation is a set of financial and legal norms regulating inter-budgetary relations arising in the process of distribution and redistribution of funds between the budgets of the budgetary system of the Russian Federation. The author concludes that the considered pool of legal norms united by a single purpose, due to their fragmentation, is of a complex character and dialectically includes legal norms of various legal entities of financial law. These include the norms of the Institute of budget revenues, the Institute of budget expenditures, individual norms of the sub-branch of tax law, the institute of legal regulation of state extra-budgetary funds, the Institute of public credit and debt, as well as the integrated financial and legal institute «budget process».