Journalists and politicians play different roles in the functional structure of the Habermasian public sphere; as such, they might be expected to have different understandings of what knowledge production and transmission might mean. This difference of understanding is more than a conflict over definitions; it is an epistemic divergence à la Fuller (2002:220), where already defined groups hold divergent understandings of what constitutes understanding. While a substantial body of work has been based on the idea of epistemic communities in the context of science and expert organizations in general, little empirical research exists to demonstrate the validity and adaptability of the concept of epistemic communities in comparative political communication research. Here, we show the cross-national validity of the concept of epistemic communities in the context of professional groups of politicians and political journalists in Austria, Finland, France, Denmark, Germany, Slovenia, Spain, Sweden and Switzerland.