The number of for-profit hospitals has increased in the United States, but their role in and outcomes for graduate medical education (GME) are unclear. To describe for-profit involvement in internal medicine (IM), general surgery (GS), and pediatrics GME by quantifying change in for-profit affiliated residency programs and comparing for-profit and nonprofit affiliated program board certifying examination pass rates. We used Accreditation Council for Graduate Medical Education and Medicare data to quantify for-profit prevalence in IM, GS, and pediatrics GME from 2001 to 2021. We used public pass rate data from the American Board of Surgeons (2017-2019; n=242 programs; 6562 examinees), American Board of Internal Medicine (2018-2020; n=465 programs; 23 922 examinees), and American Board of Pediatrics (2018-2020; n=202 programs; 9819 examinees) to model the relationship between profit status and pass rate within each specialty and across specialties combined using linear regression. The proportion of for-profit affiliated residency programs increased 400.0% in IM, 334.4% in GS, and 23.2% in pediatrics from 2001 to 2021. Bivariate linear regression revealed significantly lower pass rate in for-profit affiliated programs in IM β =-7.73, P<.001), pediatrics (β =-14.6, P<.001), and the 3 specialties combined (β =-5.45, P<.001). Upon multiple regression with addition of program characteristic covariates, this relationship remained significant in pediatrics (β =-10.04, P=.006). The proportion of for-profit affiliated residency programs has increased in IM, GS, and pediatrics from 2001 to 2021. After controlling for covariates, for-profit affiliated programs were associated with lower board examination pass rates in pediatrics with no association in IM, GS, or the combined measure.