We present the results of an investigation with the objective of analyzing the positions of six Science teachers in Tijucas, Santa Catarina on ethics in science teaching during the classroom presentation on the theme of transgenics. For data collection, we used semi-structured interviews. For the analyses, we defined three units: the nature of ethics, the ideological discourse and the moral development, as well as the attitudes of Science teachers in situations of tension. In general, we see that the teachers presented important aspects that characterize the theme of transgenics in their teaching practice, such as the questioning that values, for example, the records and the information offered by the media in general. However, some still seem to have a partial understanding of ethics in science teaching, not explaining important aspects, such as their critical and reflective positioning about the use of transgenics. We realized that such teachers have notions about the “use of ethics”, but they still face difficulties in carrying out a process of ethical training.