Background: The importance and recognition of medical ethics and professionalism has been growing. However, in Korea it is widely thought that there is still an insufficient amount of medical ethics education during resident training. The purpose of this study was to identify residents`s ethical sensitivity and coping strategies on ethical conflicts that can occur in clinical practice and research settings. Method: The survey was conducted in 16 university-based or affiliated hospitals; a total of 1,187 residents participated in the survey. A questionnaire was developed consisting of 18 questions including 7 question areas concerning residents` perspectives on ethical conflicts and professional boundaries in clinical practice or research. The seven question areas were as follows: coping and reporting mistakes (2 items), responding to impaired colleagues (2 items), relationship with colleagues, senior residents, and faculty (4 items), balancing personal and professional life (2 items), family (relatives) and friends` requests (2 items), relationships with patients and their family members (3 items), clinical research ethics (3 items). For each item, a vignette was developed on the basis of situations derived from the authors` educational and clinical experiences. To facilitate the participants` response, 4 or 5 answer options, as well a space to for open responses, were provided for each question. Results: A total of 1,072 samples (male 65.9%, female 34.1%) were analyzed. The majority of the respondents answered that if a medical mistake happens, they will report it to a faculty member and follow their instructions. Regarding impaired colleagues who may threaten patient safety, more than 70% of respondents answered that they will resolve the problem among residents themselves rather than notify a faculty member or resolve it officially. More than half of the respondents also said that if they observe non-professional or unethical conduct by either faculty members or residents, they will solve the problem by consulting with colleagues. However, more than 60% of the residents responded that they would put priority on patient care when facing conflicts between medical services and personal life. In questions about research ethics, the majority of respondents answered that they would maintain truth in managing data and research results. Conclusion: The results of this study suggest that medical ethics and professionalism curricula during residency should be strengthened to develop residents` ethical sensitivity and coping strategies concerning ethical conflicts in either clinical practice or research.