The issue of the European Court of Justice's reflection on judicial practice will be analyzed in the light of decisions that establish European practice in this tax compartment, with reference to the EU's most important revenue such as the Value Added Tax. At the time of the entry into force of the Rome Tax Convention on Circulation Tax applied in the Member States, there are different tax rates, procedural differences and the structure of the tax. The European Court's comments as well as other rulings in which the Court embodies or completes VAT legislation forms an integral part of the legal basis governing VAT because they contain provisions which determine the mechanism for implementing the directives. The decisions of the European Court have become a source of law and a component part of the legal mechanism for the harmonization of legislation governing indirect taxes in the Member States of the European Union. In our research, we will present a few examples of judicial practice, demonstrating the degree of influence of the European Court in the formation of some legal institutions of the species, as well as European tax law in general.