Civil society organisations in Central and Eastern Europe (CEE) have remained weak players compared to their counterparts in established democracies. Given the particular incentives that the EU offered for the empowerment of non-state actors during pre-accession, it has often been assumed that EU intervention improved this situation. We argue that, instead, the EU's impact was highly ambivalent. Although the EU aid and EU-induced policy reform levelled the way for established actors' involvement in multilevel politics, it reinforced some of the barriers to development that the civil society organisations face in CEE. In particular, EU measures have failed to address the lack of sustainable income, of formalised interactions with the state and of grassroot support. Drawing on the experiences of trade unions and environmental groups, we show that this ambivalent 'legacy of accession' is due to an unfortunate interrelation between various, often implicit mechanisms of the EU's enlargement regime on one hand, and particular problems inherited from state socialism and transition on the other. Acta Politica (2010) 45, 41-69. doi: 10.1057/ap.2009.18