Resumo BACKGROUND: In terms of ethical decision making, every clinical case, when seen as an ethical problem, may be analyzed by means of four topics: medical indications, patient preferences, quality of life, contextual features. The aim of this study was to compare the performance of 4th year dental students on Ethical Decision Making before and after a course on ethics. METHODS: Fourth year dental students (n = 37) from academic year 2013-2014 participated in the study. A 3-h lecture, which was about four topics approach to clinical ethical case analysis, was given to the students. The lecture was based on case scenarios related with dental ethics. After the completion of lectures,a case scenario was presented to the students to assess their ethical decision making abilities. At the end of the exam, four topics and ethical judgment were evaluated. Their performances on this examination were evaluated before and after lectures. Statistical evaluation was performed with the significance level set at p < 0> 0.05). The mean total score of the students after the course was significantly higher than before course (67.5 and 54.4, respectively; p < 0.05). CONCLUSION: More lectures should be implemented to the curriculum to increase the student awareness of ethical issues and to reach the ultimate goals of dental education.