This paper investigates the accession-related economic boom in the countries which recently entered the European Union. The analysis tests whether, on top of the standard growth determinants, the period of EU accession made a significant difference to the growth performance of the New Member States (NMS). The paper finds that the period of EU accession is characterised by significantly larger growth rates of per-capita GDP, even after controlling for a wide range of economic and institutional factors. This effect is robust and particularly strong for countries with relatively low initial income levels, weak institutional quality and less advanced financial development, suggesting that EU accession has been speeding up the catching-up process and improved the institutions of the laggards among the NMS. The prospect of EU membership which has triggered large capital inflows seems to have fostered economic growth of those NMS with lower degrees of financial depth.