This article reports on a study designed to assess the professional training in, and attitudes toward, medical ethics among the resident physicians in one university hospital in Korea. The study is based on a questionnaire, which was administered to the 470 residents at Asan Medical Center. Of the 346 (73.6%) residents who responded, 66.8% reported having completed a medical ethics course during their residency training. Serious ethical dilemmas were encountered by 69.1% of the residents at least once a year. The majority of these residents claimed to have resolved those dilemmas either alone or through discussions with colleagues. Frequently encountered issues included doctor-patient relationships, decisions to discontinue life-sustaining therapies, and do-not-resuscitate orders. Most respondents were aware of the existence of the hospital ethics committee, but did not know how to consult it. Furthermore, most participants were willing to attend medical ethics courses and believed that these should be mandatory during residency training. The results of this study suggest that hospitals should provide a well-developed medical ethics education program for resident physicians.