Researchers and other experts continue to debate whether the United States will have a shortage of physicians in the future and, if so, whether the government should act now to expand medical school capacity and encourage hospitals to train more residents. Several studies have forecast that there will be a shortage of about 100,000 to 200,000 physicians in 2020, and many medical schools are responding by expanding capacity. However, a prominent group of researchers argue that the perceived shortage of physicians is a symptom of a more fundamental problem rather than being the problem itself, and expanding the supply of physicians would merely lead to the provision of relatively low-value medical care. It is important for policymakers to determine the adequacy of physician supply as they consider provisions to reduce the uninsured and increase the demand for physician services. This paper provides a brief history of government involvement in physician workforce planning, describes and assesses the methods used by the two sides in the physician-shortage debate, and addresses the fundamental underlying views that determine many observers’ positions in this debate.