In this study, the impacts of two different “methods” for teaching ethics as part of the religious education in the Swedish upper secondary school were compared by means of a non-randomized controlled trial in two parts, involving 542 students. The question was which “method” had the greatest capacity to generate long-term ethical awareness in the students. The intervention condition consisted of students whose teachers were instructed to teach according to the Three Step Model, a teaching method influenced by research concerning (...) how moral autonomy and ethical awareness could be increased by means of instruction and training. The control condition consisted of students whose teachers were instructed to teach basically as usual but with some added guidelines. During the trial, all students were given a pre-test before the ethics section had started and a post-test 10–12 weeks after it was finished. When quantified and summarized, the results showed an advantage of the intervention condition in measure B but an advantage of the control condition in measure A ; however, the advantage of the intervention condition was clearer and stronger. Even though the intervention students did not experience a stronger development, they appeared to have learned significantly more, not least in terms of procedural knowledge in ethical problem solving. The tentative conclusion is therefore that the Three Step Model is a more effective method for increasing ethical awareness, at least if one defines ethical awareness and measures it the way it was done in this study. (shrink)