In 2006-2007, Harvard Medical School implemented a new, required course for first-year medical and dental students entitled Clinical Epidemiology and Population Health. Conceived of as a "basic science" course, its primary goal is to allow students to develop an understanding of caring for individuals and promoting the health of populations as a continuum of strategies, all requiring the engagement of physicians. In the course's first iteration, topical content accessible to first-year students was selected to exemplify physicians' roles in addressing current threats to population health. Methodological areas included domains of clinical epidemiology, decision sciences, population-level prevention and health promotion, physicians' roles in the public health system, and population-level surveillance and intervention strategies. Large-group settings were selectively used to frame the relevance of each topic, and conceptual learning of statistical and epidemiologic methods occurred in conference groups of 24 students. Finally, tutorials of eight students and one or two faculty were used for critical reading of published studies, review of problem sets, and group discussion of population health issues. To help students appreciate the structure and function of the public health system and physicians' role in public health emergencies, the course included a role-playing exercise simulating response to an influenza pandemic. The first iteration of the course was well received, and assessment of students suggested mastery of basic skills. Preclinical courses represent a progressive step in developing a workforce of physicians who embrace their responsibility to improve the health of the population as a whole, as well as the health of the patient in front of them.