The article examines the collaboration between the International Labour Organisation (ILO) and the Polish government in the interwar period. By looking at the creation and administration of knowledge, it focusses on the effects of governance. Building on Bourdieu’s idea of the official as a “social fiction”, on administration as a performative act, it shows how the mentioned collaboration used and created knowledge and how this knowledge did not only reflect reality, but how it also shaped realities. Additionally, it shows how a certain tension between idealism and administration was characteristic for the ILO as an International Organization. Hence, the article looks not only at the negotiated contents, but also at the forms of data and the modes of transferring it, especially by international comparisons. In this sense the article examines the correspondences and reports of the ILO office in Warsaw, on labour standards, and on the 8-hour day as topics by which the newly established nation state as well as the international organisation coconstituted each other. By looking at the transition phase from 1919 to 1926, it also examines the continuities in administrative practices during the state building process as well as after the Piłsudski coup d’état of 1926.