This paper addresses the politicization of public institutions through the case of national ombudspersons. While there is an established literature on the politicization of top public officials, we lack research on the politicization and / or de-facto independence of supreme or supervisory bodies, including ombuds institutions. In this paper, we combine the insights of three bodies of literature in order to build a framework for the empirical study of national ombuds institutions: Literature (1) on the independence of public institutions, in particular ombuds and regulatory agencies, (2) on politicization and party patronage in state institutions, and (3) on career patterns and selection criteria of top public officials and the administrative elite. We then discuss these issues on the basis of an empirical field study of the Austrian om-buds institution: First, drawing on a socio-demographic analysis of ombudspersons we identify common features of their profiles and career paths. We find that overall the ombudspersons represent a relatively homogenous group, but the political party represents an explanatory variable for some of the ombudspersons’ characteristics. The second set of empirical results, drawing primarily on qualitative interviews with case-handling staff, demonstrates that despite the institution’s public efforts and many interviewees’ reassurances that the AOB is independent and acts as such, there are several areas in which party-related positions become visible in the AOB’s work. These results are integrated into a typology on the effects of political appointment modes of ombudspersons, which should enable further research in this field.