The EU accession brought significant changes in the competition rules concerning undertakings - now the Community competition rules are directly applicable to Hungarian undertakings as well. At the same time these rules were not completely unknown for the Hungarian undertakings and enforcers. To fulfil the obligation of approximation of the law, undertaken in the Association Agreement, the Hungarian competition law continuously followed and took over the most important norms and principles of the EC competition rules, furthermore the approximation of Hungarian competition law with the Community norms is continuous from the accession. So the accession did not cause shock in this field. Which really resulted some change rather arise from the enforcement system, since GVH has to apply the Community rules.