Political science research of interest groups and political parties in EU policymaking processes represent two largely separate study fields between which cross-fertilization remains very limited. In this paper we elaborate why this gap exists and why it should be addressed in order to improve our understanding of EU legislative politics. Both literatures present a different image of EU legislative policymaking. Although most scholars of EU party politics endorse the notion that parties politicize EU legislative politics, scholarship of interest groups tends to portray the EU as a rather de-politicized system in which expertise-based exchanges between societal interests and bureaucratic agencies are pivotal. The paper we will present, which is part of a large EU-wide comparative project on interest group politics, argues that, despite the absence of exclusive and organizational party-group links, groups and parties get tied by similar positions on political cleavages. Evidence on party and group involvement in the policy process surrounding 100 legislative acts adopted by the EU between 2008 and 2010 is used in order to substantiate the role of partisanship in EU legislative lobbying processes.
