Past and current impacts of the supply of foreign medical graduates (FMGs) on the total physician supply and on the availability of physician services are reviewed, and the possible future role of FMGs is forecasted. The relationship of the levels and changes in FMG supply to legislative decisions of the past three decades is also addressed, with attention to post-World War II legislation, the Immigration and Nationality Act of 1965, legislative changes in the mid-1970s, the Health Professions Educational Assistance Act of 1976, and recent legislation. The numerical impact of FMGs on specialty distribution, activity distribution, and practice location is analyzed, and information is provided on the performance of FMGs on standard qualification examinations. The activity and specialty patterns and practice locations of U.S. citizen FMGs are also assessed. Over the 1970-1979 period, FMGs constituted about one-fifth of the annual active physician supply, but accounted for one-third of the growth in physician supply. It is estimated that the FMG supply will grow at a slower rate in the future than in the past: by about 35% between 1981 and the year 2000, with most of the growth occurring in the early years of the period as a result of the return of U.S. FMGs to the United States. (SW)