The ‚Auslandsdeutsche‘, emigrants from Germany living abroad, played an important role in Nazi ideology and propaganda. They were seen as outposts of the German nation to be mobilised for the political purposes of the Third Reich. In this context, research into emigration took on special importance in order to identify and localise individuals with German origins all over the world. Researchers following a different, non-political agenda were marginalised and suppressed. The controversy analysed in this paper between the Bonn-based scholar Joseph Scheben and the „Deutsches Ausland-Institut“ (DAI) in the early 1940s on the methodology of research into emigration paradigmatically demonstrates this development. Being interested in emigration as such, Scheben belonged to a somewhat older research tradition based on international cooperation. The DAI, on the other hand, argued from the viewpoint of Nazi racial science and political rationale in line with the Foreign Office in Berlin. Research into emigration in National Socialism was to be conducted for political purposes and therefore kept secret.