Recent changes in the health care environment have directed increasing attention to the recognized oversupply of specialists and relative lack of primary care physicians. Despite this imbalance and the need for more primary care physicians, US medical schools are not producing them in adequate numbers. To effect change in the production of primary care physicians, a comprehensive approach that addresses key factors in medical student specialty choice is needed. This article discusses such factors and how they affect medical students during the course of their training. Issues concerning primary care specialty choice and the physician work force are important to the development of the future US health care system.