Reforming the tax mechanism in agriculture should include not only the optimal size of the tax burden, but also responsible for the structure of payments and fiscal instruments applicable level of economic development of Ukraine in general and agriculture in particular. In the light of current integration processes in reforming the national system of taxation should be based on the fact that one of the basic principles of the WTO is no tax discrimination. This includes ensuring that national tax regime, in which imported goods granted the same tax conditions as domestic products. The article further scientific substantiation of directions of the national system of state support for agricultural producers, in particular through the mechanism of taxation.The reform of state aid involves creating comfortable conditions for small farms and stimulate production of products with added value. The main principles of state support should be targeted and transparency.