This paper examines undergraduate medical ethics education in the United States during its 25-year history. Included is a brief description of early efforts in medical ethics education and a discussion of the traditional model of ethics teaching, which emphasizes the knowledge and cognitive skills necessary for ethical decision making. The authors also discuss alternatives to the traditional model that focus more directly on students' personal values, attitudes, and behavior. Current areas of consensus in the field are then explored. Finally, the authors identify three incipient trends in medical ethics education--toward increased emphasis on everyday ethics, student ethics, and macroethics. Throughout the paper, examples of specific courses and curricula are used to illustrate the modes and trends described.