A b s t r a c t The 1999 debate of the American College of Medical Informatics focused onthe proposition that medical informatics and nursing informatics are distinctive disciplines that require their own core curricula, training programs, and professional identities. Proponents of this position emphasized that informatics training, technology applications, and professional identities are closely tied to the activities of the health professionals they serve and that, as nursing and medicine differ, so do the corresponding efforts in information science and technology. Opponents of the proposition asserted that informatics is built on a re-usable and widely applicable set of methods that are common to all health science disciplines, and that ''medical informatics'' continues to be a useful name for a composite core discipline that should be studied by all students, regardless of their health profession orientation. Received for publication: 1/8/00; accepted for publication: 1/18/00. burgh organized the debate to focus on professional training and professional identities in informatics. As with previous ACMI debates, 1-3 the issues were intentionally polarized on a specific proposition:Resolved: Medical informatics and nursing informatics are distinctive disciplines that require their own core curricula, training programs, and professional identities. This is a classical debate, the purpose of which was not to achieve consensus or to declare a winning or losing debating team, but rather to bring attention to contemporary views of the similarities and differences of the health-related disciplines involved in informatics training, research, and development. What follows is an edited transcript of that debate.