This article seeks to discuss the fairness of the tax system and the options that perspective of fiscal federalism. The article argues that there was a profound evolution in terms of fiscal discipline - through, among several causes of a progressive abandonment of the single tax theories and focus efforts on enhancing a policy of financial revenues of the state. A fiscal policy that includes increasing the principles of distributive justice, substantive equality, efficiency, morality and state impersonality, and greater economic rationality that makes possible an optimization of storage with a view to achieving the core activities of the state. However, to achieve tax justice there is still a great journey ahead, especially as regards the creation of a context for the viability of a tax reform, especially to avoid deformation of the constitutional text through successive cuttings by constitutional amendments - many of dubious legality - and the weakening of the rights arising from such behavior.