Students of public administration have often focused on behaviour and attitudes without relating them explicitly to bureaucratic structure. They have also concentrated on structural descriptions, and on reorganization processes. These steps are, beyond doubt, necessary and important. However, connecting structure and policy making in order to learn about the consequences of alternative arrangements can be assumed to be the ultimate concern of academics as well as of practitioners. The relationship between formal structure and actual decision behaviour is an issue of enduring theoretical interest. At the same time, insights into how organizational change might affect policy-making and performance are crucial for most high-level officials. I will proceed by identifying theoretical components that assign a role to the formal administrative structure in this respect. The empirical studies I draw on are mainly confined to research on central government bureaucracies at the national level, and how their structures affect substantive policy making.