This article deals with the moral responsibility of information systems (IS) designers in the context of professional use. In the exercise of this moral responsibility, economic and social dimensions will be specifically discussed in the sense that IS have an impact on the development and sustainability of organizations. The first part of this article is devoted to an overview of computer ethics. The second part presents our orientation (critical research) and our approach (which considers IS as power devices), and concludes on the need to think a true engineering of responsibility. In the third part, our contribution to this engineering is presented in the form of a three-level model which helps to reveal how a general vision and linked ethical values are gradually embodied in structuring principles and binding standards. JEL Codes: M15, M14, L86, L29