Objective: The Bioethics Teaching in Secondary Education (Project BEST) aims to promote the teaching of bioethics in secondary schools. This paper describes the development and implementation of the programme in Portugal. Design: Programme development involved two main tasks: (1) using the learning tools previously developed by the US Northwest Association of Biomedical Research and the Council of Europe and (2) applying the project in classrooms, conducting lectures on bioethics for students and teachers, and then using the previously developed learning tools. Setting: 32 schools representing the most densely populated regions of Portugal. Methods: Two surveys, based on previously validated measures, were used to evaluate the project. Results: The surveys were answered by the 179 students and 16 teachers attending a conference held by the project, which concluded the project's implementation phase. The findings point to the positive impact of this project. Conclusion: Based on evidence collected to date, it is clear that (1) students can develop reflective skills using this kind of an approach, (2) the project is well suited to secondary school syllabuses and to the age range of students from secondary schools, and (3) the teaching of values should start earlier at school, thereby helping young people develop a critical perspective on problems linked to scientific development and its implications on human health.