After 20 years of the Single European Market , with the liberalization and the free competition between Member States , there are still challenges that must be removed to make it a reality. The elimination of tariffs within the European Community was one of the greatest successes of this project. However, the current economic crisis favors the protectionism in the Member States , although the Heads of State and Government recognized that complement the implementation of the single market is one of the paths to exit from the crisis and this necessarily imply greater economic and fiscal coordination.In this context, it is important to know the influence that the process of European integration has had on the approximation of the tax systems and their relationship to the economic convergence in the Member States.The project proposes to establish a seminar that can become a forum for debate and reflection on the importance of the European integration process , with the participation of researchers, students, social workers , etc. A seminar, a workshop and a final conference will spread the realized research and the edition of the works the form to have a high impact.