The author outlines the intertwining roles of the Educational Commission for Foreign Medical Graduates (ECFMG), which is celebrating its 50th anniversary in 2006, and the National Board of Medical Examiners (NBME) in meeting needs for assessment of international medical graduates. Both organizations had early histories focused on a protective role: ensuring that only the most qualified foreign-trained doctors could train or practice in the United States. The two organizations have interacted throughout the ECFMG's 50-year history to improve the assessment of internationally trained doctors. As both the ECFMG and the NBME have matured, their missions have expanded to include improvement of medical education and assessment around the world. Much of the success of each organization in fulfilling its mission can be attributed to their close collaboration through the past 50 years.