Revision with unchanged content. "The United Nations Secretariat - Bureaucratic Authority in Peacekeeping and Humanitarian Affairs" explores the capacity of the international bureaucracy of the United Nations Secretariat for bureaucratic authority. The theoretical framework conceptualizes bureaucratic authority along the three dimensions of expertise, rational-legal procedures, and moral appeal. It thereby draws from the classical conceptions by Max Weber, as well as more recent findings. Two empirical in-depths case studies frame the argument. The first addresses the Department for Peacekeeping Operations (DPKO), the second the Office for the Coordination of Humanitarian Affairs (OCHA). The findings suggest that through their close involvement in the multilateral decision-making process, both DPKO and OCHA are able to bring to bear their significant informational, material as well as ideational resources. International bureaucracies like the UN Secretariat thus are not only in authority, but have to be seen as authorities in their own right as well.