This paper describes the motivating factors of a large and a small sized research firm in becoming ISO 9000 certified. It provides a short introduction of the basic aim, requirements and misunderstandings about the ISO 9000 standard. Different ways of implementation of such a system are illustrated by the example of Infratest Burke. But what are the benefits of an ISO 9000 certification? Is it really worthwhile to spend a lot of money just to become certified? Meanwhile, the quality systems of both companies have been implemented for some years. The authors illustrate and discuss the experience they have made with their ISO 9000 quality system after certification. The paper gives an insight into different impacts of the quality system on the internal organization and the workflow. These examples show how ISO 9000 assists a continuous improvement and optimization process. They demonstrate that the ISO 9000 standard can be an important vehicle for a quality focused management.