Creating a true continuum of medical education from admission to medical school throughout a lifetime of professional learning is easier said than done. To do so, the various components on the continuum must be explored to determine where appropriate links might be made. The author considers selected concepts and evidence from the theory and practice underlying continuing medical education (CME) and continuing professional education (CPE) insofar as CME and CPE can inform undergraduate medical curricula, including its current innovations. Five conceptual and empirical approaches from CME and CPE are discussed in detail: social learning theory, how physicians learn and change, competence in business and the professions, how professionals learn in practice, and lifelong self-directed learning. Then the author describes the implications of these approaches for the ongoing development of undergraduate medical education. (1) The entire learning environment, and not merely discrete aspects such as curriculum content, must be examined and fully utilized to benefit learning. (2) The importance of the contexts in which learning occurs must be emphasized in several ways. (3) Learning should be centered around clinical problems. (4) The many benefits of small-group learning and other ways of learning from colleagues should be emphasized. (5) The undergraduate curriculum should emphasize the development of students' feelings of self-efficacy to ensure that students become physicians who are confident about their abilities. (6) CME research and CPE research reinforce the efforts in undergraduate medical education to emphasize the early development of students' process skills as well as content mastery.