Using the definitions of "medically underserved areas" developed by the California Health Manpower Policy Commission and data on physician location derived from a survey of California physicians applying for licensure or relicensure between 1984 and 1986, we examined the extent to which different kinds of primary care physicians located in underserved areas. Among physicians completing postgraduate medical education after 1974, board-certified family physicians were 3 times more likely to locate in medically underserved rural communities than were other primary care physicians. Non-board-certified family and general physicians were 1.6 times more likely than other non-board-certified primary care physicians to locate in rural underserved areas. Family and general practice physicians also showed a slightly greater likelihood than other primary care physicians of being located in urban underserved areas.