This article describes the execution of the tax obligation by a third party. The regulation of the fulfillment of tax obligations by a third party in Art. 45 of the Tax Code of the Russian Federation (before amendments), in the judicial practice and clarifications of the Ministry of Finance of the Russian Federation, as well as exceptions to the principle of self-fulfillment of tax obligations are investigated. Analyzed the arguments of the Constitutional Court of the Russian Federation in favor of a general ban on the fulfillment of tax obligations by a third party and its criticism. The peculiarity of this work is that it considers art. 45 of the Tax Code of the Russian Federation, which regulates the fulfillment of a tax obligation by a third party, both before and after the amendment.