Extension of the acquis to the new Member States raises a number of questions relating to the temporal reach of Community rules. This paper examines a general doctrine underlying the solutions. It presents a classic intertemporal doctrine, which has influenced early jurisprudence of the European Court of Justice. Then, it comments upon the cases brought before the Court in the context of the 1995 enlargement, the entry into force of the EEA Agreement and also the Europe Agreements. These cases evidence substantial differences in the attitudes taken by the national courts, the Advocates General and the Court. One reason for divergence is that the line of reasoning adopted by the Court carries several interpretative difficulties characteristic of the classic doctrine. Secondly, controversies arise in the instances where the Court takes a proactive attitude, which is difficult to reconcile with the traditional scheme. It is argued that greater attention to the structure underlying the reasoning would help to strengthen justification of the Court's solutions and enhance their predictability. This is the more important, as the forthcoming accessions are likely to bring new disputes relating to the effects of Community law in time.