Background Little is known about how the education and specialty certification of intensive care unit nurses influence patients’ outcomes. Objective To examine the relationships between critical care nurses’ education level and specialty certification, their individual psychosocial beliefs about their place on the intensive care unit team (in relation to 3 factors: professional identity, self-efficacy, and role clarity), and their perceptions of evidence-based practices used in the intensive care unit. Methods A cross-sectional survey was emailed to nurses in 12 adult intensive care units within 6 hospitals in a single, integrated health care system. Results Of 268 respondents, 180 (71%) had a bachelor of science degree or higher, and 71 (26%) had critical care certification. Compared with noncertified nurses, certified nurses reported greater knowledge of spontaneous breathing trials (4.6 vs 4.4 on a 5-point scale, P = .03) and lung-protective ventilation (4.2 vs 3.9, P = .05). Certified nurses reported significantly higher self-efficacy (4.5 vs 4.3 on a 5-point scale, P = .001) and role clarity (4.4 vs 4.2, P = .05) than noncertified nurses. Certification was also associated with greater perceived value in specific practices (daily interruption of sedation: adjusted odds ratio 2.5 [95% CI, 1.0-6.3], P = .05; lung-protective ventilation: adjusted odds ratio, 1.9 [95% CI, 1.1-3.3], P = .03). Education level was not associated with greater knowledge of or perceived value in evidence-based practices. Conclusions Nursing specialty certification was associated with nurses’ individual psychosocial beliefs and their perceptions of evidence-based practices in the intensive care unit, whereas education level was not. Supporting nurses in obtaining specialty certification could assist with the adoption of evidence-based practices as a means to improve quality of care in the intensive care unit.