Abstract this article examines the impact of the 2004 and 2007 enlargements on cfsp committees. It aims to determine in which manner enlargement has affected the deliberative nature of cfsp committees and in which ways formal and informal mechanisms have contributed to overcoming deadlock in the decision-making process. The article concludes, first, that formal and informal adjustment mechanisms have ensured a smooth functioning of the cfsp. Second, socialization and consensual decision-making are still prevalent in the practice of cfsp bodies and have prevented deadlock. Moreover, learning processes remain crucial in committee governance, allowing newcomers to familiarize themselves with cfsp practices. As regards legitimacy, however, a less positive assessment can be made. By increasing the informality of cfsp negotiations and the role of ‘like-minded’ groups, and decreasing the role of formal meetings, enlargement may have contributed to an erosion of the cfsp’s democratic legitimacy.