European Union (EU) studies is known as a fragmented and interdisciplinary field. Drawing on bibliometric methods, this article presents a novel approach to examining the alleged lines of fragmentation in EU studies. It maps the network structure arising from the citation practices in journals concerned with EU studies by analysing 2,561 documents, containing 66,162 references, published in four authoritative EU journals in the period 2003–2010. The article finds: (1) a complex network of EU and non-EU sources clustering around different bordering disciplines, particularly Political Science, Comparative Politics, International Relations and Public Administration; (2) that the two core journals – Journal of European Public Policy and Journal of Common Market Studies – play an integrating function by holding the various subfields of EU studies together; and (3) a transatlantic divide in communication practices of EU scholars.