Following the example of the many organizations in the United States which have a code of ethics, an increasing interest on the part of companies, trade organizations, (semi-)governmental organizations and professions in the Netherlands to develop codes of ethics can be witnessed. We have been able to escort a variety of organizations in this process. The process that organizations must go through in order to attain a code involves a variety of difficult decisions. In this article we will, based on our experiences, describe twelve dilemmas which will have to be 'solved' during the development of such a code. When one or more of these dilemmas is ignored or an ungrounded choice is made, the effectiveness of the code will be negatively affected. Furthermore, the twelve dilemmas could be used as twelve dimensions to exemplify organizational codes of ethics. In this article we will also discuss a method to organize ethics within the organization. This will serve as a guide as to how, with respect to the dilemmas described, adequate considerations can be made. The article will be concluded with a description of our experiences at the Dutch Schiphol Airport. This case demonstrates how the aforementioned reasoning can be applied in practice.