Shortages of primary care physicians have historically affected rural areas more severely than urban and suburban areas. In 1970, the University of Washington School of Medicine (UWSOM) administrators and faculty initiated a four-state, community-based program to increase the number of generalist physicians throughout a predominantly rural and underserved region in the U.S. Northwest. The program developed regional medical education for three neighboring states that lacked their own medical schools, and encouraged physicians in training to practice in the region. Now serving five Northwest states (Washington, Wyoming, Alaska, Montana, and Idaho), the WWAMI program has solidified and expanded throughout its 30-year history. Factors important to success include widespread participation in and ownership of the program by the participating physicians, faculty, institutions, legislatures, and associations; partnership among constituents; educational equivalency among training sites; and development of an educational continuum with recruitment and/or training at multiple levels, including K-12, undergraduate, graduate training, residency, and practice. The program's positive influences on the UWSOM have included historically early attention to primary care and community-based clinical training and development of an ethic of closely monitored innovation. The use of new information technologies promises to further expand the ability to organize and offer medical education in the WWAMI region.