Purpose: To compare perceived competence and self-efficacy (SE) among Swedish operating room (OR) nurses and registered nurse anesthetists (RNAs), and to evaluate the relationship between SE and competence, gender, age, and years of experience. Design: Comparative cross-sectional survey. Methods: Two validated questionnaires, Perceived Perioperative Competence Scale-Revised and General Self-Efficacy Scale, were sent to members of the Swedish Association of Health Professionals (n = 2,902). Findings: The response rate was 39% (n = 1,033). OR nurses showed significantly higher scores on Perceived Perioperative Competence Scale-Revised subscale foundational knowledge and leadership as well as General Self-Efficacy Scale scores compared with RNAs. The RNA group showed significantly higher empathy scores compared with OR nurses. Among the OR nurses professional development made the strongest contribution to SE and proficiency among the RNAs. Conclusions: These results suggest that there are differences in perceived competence and SE between OR nurses and RNAs. Gender may be an independent factor affecting SE.