The interactions between religion and politics in the European integration process are the focus of increasing attention in political and academic debates. However the body of research that has been developing for several years relates mainly to the representation of religious interests at the European Commission. The influence of religious actors and networks within the European Parliament give rise to many suppositions, ambitions or fears, but there is nothing tangible with which to evaluate them. Studying the preferences of European legislators reveals the conditions in which religion exerts an influence. This analysis also aims to provide useful information on the socialisation capacities of the European Parliament vis-a-vis its members by focusing on an aspect of the normative orientations of MEPs that has been the subject of very little study to date. Furthermore, the denominational dimension is a particularly key factor in understanding partisan formations in the European Parliament and possible divisions between old and new Member States. Finally, the religious variable provides an opportunity to investigate the way in coalitions are formed, particularly in relation to those matters that continue to move higher up the EU agenda (the fight against discrimination; ethical issues; geopolitical stakes; the accession of Turkey, etc.).