For many decades, international medical graduates (IMGs) have had a major role in staffing the health-care system of the United States. This occurs despite the great difficulty that non-citizens have in enrolling in US medical schools. Rather, many IMGs enter the US health-care system as postgraduate trainees at the residency or fellowship level. As an example, in the 2013 National Residency Match, IMGs comprised 36.8% of the 34,355 match registrants and 5,775 IMGs matched into their preferred specialties that year. IMGs comprise an even greater proportion of the fellowship application pool, representing 43% of applicants in 2011 to the adult subspecialties of cardiovascular disease; endocrinology, diabetes, and metabolism; gastroenterology; hematology and oncology; infectious diseases; nephrology; pulmonary and critical care medicine; and rheumatology; as well as neonatal-perinatal medicine.