This article examines the institutionalization of Community governance in the area of audit in the period prior to the establishment of the European Court of Auditors. Drawing on the literature on institutionalism and early supranational governance, it puts forward an original framework for analysing institutional dynamics that distinguishes between the institutional and the organizational/individual level, and between political and social space both inside and outside the institution. It provides a way of identifying the functions of institutions-in-the-making and distinguishing the locations of actor interactions. It then applies this framework and expectations to a longitudinal analysis of the Audit Board of the European Communities, based on the close reading of the minutes of more than 200 meetings over two decades. It argues that the rule system and normative order of the Board, as well as Community audit arrangements more broadly, resulted from various patterns of intra- and inter-institutional interaction that brought resistance, conflict and contestation.