Typically, a distinction is made between argumentation and explanation based on their different illocutionary aims. While the aim of argumentation is to provide support for the acceptability of a particular thesis by means of other statements, the aim of explanation is to provide understanding of a phenomenon, regularity, etc. Although this distinction is well-founded, it obscures certain interesting interactions between explanation and argumentation. This paper identifies a particular type of explanations that presuppose argumentation in their favor. These explanations refer, at least in part, to pieces of knowledge that had not been part of the preexisting knowledge base of science. Their epistemic status is therefore problematic and they require separate justification. The success of this justification (a speech act of argumentation) is one of the felicity conditions of (the speech act of) explanation. The paper proposes a general scheme of argumentation in favor of an explanation. It combines subordinative and coordinative argumentation whose aim is to show that the explanation satisfies the (often implicit) criteria of adequacy. The scheme is briefly illustrated on an example of empirical research in International Relations.