OBJECTIVE: To describe the views of residency program directors regarding the effect of the 2010 duty hour recommendations on the 6 core competencies of graduate medical education. METHODS: US residency program directors in internal medicine, pediatrics, and general surgery were e-mailed a survey from July 8 through July 20, 2010, after the 2010 Accreditation Council for Graduate Medical Education (ACGME) duty hour recommendations were published. Directors were asked to rate the implications of the new recommendations for the 6 ACGME core competencies as well as for continuity of inpatient care and resident fatigue. RESULTS: Of 719 eligible program directors, 464 (65%) responded. Most program directors believe that the new ACGME recommendations will decrease residents' continuity with hospitalized patients (404/464 [87%]) and will not change (303/464 [65%]) or will increase (26/464 [6%]) resident fatigue. Additionally, most program directors (249-363/464 [53%-78%]) believe that the new duty hour restrictions will decrease residents' ability to develop competency in 5 of the 6 core areas. Surgery directors were more likely than internal medicine directors to believe that the ACGME recommendations will decrease residents' competency in patient care (odds ratio [OR], 3.9; 95% confidence interval [CI], 2.5-6.3), medical knowledge (OR, 1.9; 95% CI, 1.2-3.2), practice-based learning and improvement (OR, 2.7; 95% CI, 1.7-4.4), interpersonal and communication skills (OR, 1.9; 95% CI, 1.2-3.0), and professionalism (OR, 2.5; 95% CI, 1.5-4.0). CONCLUSION: Residency program directors' reactions to ACGME duty hour recommendations demonstrate a marked degree of concern about educating a competent generation of future physicians in the face of increasing duty hour standards and regulation.