At first sight, it is not always clear why national courts refer specific questions on the interpretation of Community law to the European Court of Justice (ECJ). One of the cases the potential relevance of which cannot be assessed on the basis of the text of the referral, is the case of Magoora, in which a Polish regional administrative court referred questions to the ECJ on Poland's power to retain a transitional arrangement. This article examines the transitional arrangements applicable in Poland (and the other Member States) as regards their compatibility with Community law.