This article is devoted to the legal issues of the tax process regulated by the Russian Federation Constitution and the RF tax legislation. Besides the article provides analysis of the structure of the-RF-only competence and mutual competence of the Russian Federation and its subjects in taxation field, peculiarities of federal economic services activity and state-regulated accounting system. Author outlines the correlation between the common principles of taxation and the tax process, reveals the legal conditions for single market and common financial area foundation, unification and predictability of state and taxpayers actions in the taxation sphere, proves the existence of the tax process as the multistage legal institute.