The competition law of the European Union and the competition law of each Member State are overlapping one another. The enforcement of competition law is divided between the Commission of the E.U. and the competition authority of each Member State, therefore, it is interesting and useful to compare decisions at the two levels dealing with the same or a similar topic. The present work compares the MasterCard Decision of the Commission of the E.U. and the 2009 decision of the Hungarian Competition Authority concerning multilateral interchange fees. It highlights the most important problems and critiques regarding the later decision.