Having studied emergence of ethics discourses in the engineering profession, the development of ethics courses, shows that the humanities generally are carried by an ideal, either encyclopaedic, or social, both opposing to a strictly professional approach of the training. But rhetorics and educational projects are only indicators of the ethical concerns of the engineers. So, having clarified the limits of the field of engineering ethics, I set up an inquiry with graduated engineers, in order to study their professional ethics. It seemed that this one is determined by the professional identity of the engineers. The optimists seem less worried than the others of the negative impacts of techniques; Manager show themselves very sensitive to the importance of the human factor, the experts defend the neutrality of their work and reject the idea of a personal responsibility for the ultimate end of the techniques to which they take part. But the engineers' ethics also depends on political attitudes: those of right-hand side, more optimistic towards techniques, prefer a regulation by the profession itself, those of left-handler are more opened to a democratization of the decisions. But, finally the vision of the majority is technocratic and the position of the engineers, often at distance of the res publica, leaves them away from a major concern of the ethics of technology : technology assessment. Finally, the ethics of the engineers depends on religious attitudes. So, the Catholics are favorable to a codification of the ethics, but because they are too confident in the positive impact of the techniques in the service of the Human being, their desire of ethical guidelines meets little the question of the risk which is in the heart of the ethics of the technologies.
