An inquiry committee of the Dutch parliament concluded that the capital Amsterdam - and especially the famous Red light district - is a centre of national and international organized crime. The city of Amsterdam set up a project to develop and implement an administrative approach to combat the organized crime problem: the Van Traa-project. This project is internationally recognized as a successful example of such an approach. Elaborating on an evaluation study this article critically analyses the policy theory and the effects of this project. This analysis shows that the assumptions that underlie the project are debatable, or proved hard to employ in practice. Despite the fact that in the policy plans the necessity of a multi-agency approach is stressed, external parties such as the police and the public prosecutors department take a rather passive stand, preventing the administrative approach of becoming a part of a truly integrative approach to organized crime. Furthermore, this article proves that it is hard to confirm this successfulness in a sound scientific manner. Many positive results can be observed, but it remains unclear to what extent these results have an impact on organized crime. Although some indications of a plausible impact of the measures taken in the Van Traa-project on organized crime were found, this article also refers to some indications of counterproductive effects.