The public sector is in a phase of reform and transition and thus many thousands of workers are experiencing change. The extent and implementation of new public management (NPM) reforms has been studied extensively in a comparative perspective, while the role of employees’ representations in the reform process remained widely neglected. This article attempts to contribute to filling this gap. The role and strength of public sector trade unions will constitute the core of this paper which aims at answering two main aspects. Under which circumstances were trade unions able to influence new public management reforms? And which strategy led to a change in their relative power? These questions will be assessed in a comparative study of the introduction of diagnosis-related groups (DRGs) into the German and British hospital sector, drawing on an empirical analysis of magazines published by the ministries of health, health insurers/services and trade unions.