How can a course on engineering ethics affect an undergraduate student's feelings of responsibility about moral problems? In this study, three groups of students were interviewed: six students who had completed a specific course on engineering ethics, six who had registered for the course but had not yet started it, and six who had not taken or registered for the course. Students were asked what they would do as the central character, an engineer, in each of two short cases that posed moral problems. For each case, the role of the engineer was successively changed and the student was asked how each change altered his or her decisions about the case. Students who had completed the ethics course considered more options before making a decision, and they responded consistently despite changes in the cases. For both cases, even when they were not directly involved, they were more likely to feel responsible and take corrective action. Students who were less successful in the ethics course gave answers similar to students who had not taken the course. This latter group of students seemed to have weaker feelings of responsibility: they would say that a problem was "not my business." It appears that instruction in ethics can increase awareness of responsibility, knowledge about how to handle a difficult situation, and confidence in taking action.