While interdisciplinarity is not a new concept, the political and discursive mobilisation of interdisciplinarity is. Since the 1990s, this movement has intensified, and this has affected central funding bodies so that interdisciplinarity is now a de facto requirement in successful grant application. As a result, the literature is ripe with definitions, taxonomies, discussions and other attempts to grasp and define the concept of interdisciplinarity. In this paper, we explore how strategic demands for interdisciplinarity meet, interact with and change local research practices and results of higher education and research. Our aim is to question and trace the consequences of applying the slippery and difficult term interdisciplinarity in research. The paper is based on ethnographic fieldwork in a Danish interdisciplinary research programme, where we observed and analysed practices of writing, publishing, collaboration and educational development in five different research projects. We show how the call for interdisciplinarity was mobilised in a way that rendered the incentives and motives behind the programme unclear. Furthermore, we argue that the absence of clear definitions and assessment criteria produced a dominant, all-inclusive, but vague, configuration of interdisciplinarity that affected the research outcome, and ultimately, promoted and reproduced the existing monodisciplinary research and power structures.