This article provides an estimate of the effects of health reform on the US physician workforce requirement. Its basic methodology is to extrapolate current patterns of staffing within managed care plans to the reshaped health care system of the year 2000. In this analysis it is assumed that 40% to 65% of Americans will be receiving care from integrated managed care networks in the near future, and that all citizens will be covered by some type of health insurance. On the basis of these assumptions, this article forecasts that in the year 2000, (1) there will be an overall surplus of about 165,000 patient care physicians; (2) the requirement and supply of primary care physicians will be in relative balance; and (3) the supply of specialists will outstrip the requirement by more than 60%. In summation, it appears that national health reform--based largely on an expansion of managed care networks--will have significant impact on the US physician workforce. Concerns have been raised by others that health system reform's shift toward more primary and preventive care will be stymied by workforce availability. This study underscores this concern to some degree. However, the evidence presented herein suggests that the issue is not so much a primary care provider shortage as a specialty care surplus.