The European Court’s comments as well as other rulings in which the Court embodies or completes VAT le-gislation forms an integral part of the legal basis governing VAT because they contain provisions which determi-ne 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.