The present study aimed at providing an overview of the most common themes of research into medical education. Changes in frequency of occurrence of these themes over time and differences between US and European journals were studied. The most productive institutions and researchers in the field were examined. A content analysis was carried out on 10,168 abstracts extracted from the six most influential journals in medical education published since 1988. Twenty-nine major themes were identified, of which student assessment, clinical and communication skills, clinical clerkships, and problem-based learning were the most prominent ones. Some of these themes, such as multiple-choice examinations or computer-assisted instruction seemed to have had their day, whereas other topics, such as the study of clinical clerkships, clinical reasoning, and scholarship in education were on their way up. Medical education research turned out to be a thoroughly international affair to which both US and European research centers contribute. The medical education literature shows an overwhelming emphasis on the preparation of medical students for professional practice. Moreover, the emphasis is very much on the individual student; most research seems to have been conducted with a psychological perspective in mind. It is argued that medical education research would profit from broadening its scope, including sociological, economical, ecological, and system perspectives. These perspectives might bring answers to new questions relevant to the quality of medical education. It is suggested that medical education is in need of moving beyond the conventional effectiveness-driven research approach to a more theory- and discovery-driven approach.