ABSTRACT This thesis aims to investigate information processing and decision making in organizations. The overall perspective is dedicated to explore initiatives that managers could use in order to improve information processing and decision making in their organizations. I start by a theoretical overview of the literature and research in the field of information processing and decision making. Then, I proceed, thanks to a case study, to an analysis of a tax administration. Theories will inform comparison and help the reflective analysis concerning the work processes. Finally, I will suggest ideas for change and possibilities of adaptation. The literature review, as well as the case study, indicates multiple relevant aspects to the analysis of information processing and decision making. For example: quantitative analytical techniques, cognitive aspects, the conception of knowledge workers, individual and group work, leadership, the impact of technology, organizational model, continuous learning, and others. Organizational model has to taken into account individual careers and technological developments which put central emphasis on information processes and decision making. Information processing and decision making are important part of the normal functioning of bureaucracies, both private and public. Information processing and decision making can not be simply considered as a commodity: they imply to consider the organizational work to be both technical activity as a social one. An appropriate atmosphere is important for every organization – where should dominate trust, open communication, interaction and negotiation. In this respect, managers have to understand their socio-technical role within the organization. Technological resources and quantitative techniques are important to support the development of speedy and ever changing activities. Continuous learning is therefore a necessity and should happen through informal practices at work as well as traditional teaching. The demands of adaptation are so strong that the behavioral perspective needs to be thought within a common organizational demand.