How do independent agencies tasked with expert regulatory roles gain and maintain trust among policy stakeholders? This paper explores the question through a study of influenza pandemic response processes in a European public health agency. In particular, is asks whether reputation-seeking could have a decisive impact on response actions taken by the agency. In doing so, the analysis tests whether reputation-seeking behaviors discovered in US federal agencies also exist in Europe. It also breaks new methodological ground: where previous analyses of agencies' reputation-seeking have relied on retrospective studies, this analysis uses a unique, first-hand participant-observer record and interviews collected within an agency at the height of the "swine" flu pandemic (October-December 2009). The paper shows that reputation-seeking among audiences of European health departments and health care providers was a principal driver of several pandemic response actions.