Background: Patient safety is impacted by the personality traits of critical care nurses and is correlated with their competence, ability to handle stress, and to manage with burnout. This study aimed to investigate the relationship between the personal characteristics of the critical care nurses and their competence. Research design: A descriptive cross-sectional research design was utilized. Setting: This study was conducted in intensive care unit at Al Mobara Hospital and Assiut University Main hospital from August 2022 until the end of February 2023. Sample: A convenience sampling of 186 critical care nurses who provide patient care were asked to participate in the study. 120 nurses responded to the online survey, which was distributed to them. Tools: Two tools were utilized in this study; personality characteristic of critical care nurses assessment and nursing competence assessment. Method: The researcher transmitted the online link of the questionnaire to participants in Telegram App group or via their professional email addresses for completing the questioner. Results: 69.2% of the studied nurses had an expert level of nursing competency. There is a significant positive correlation between extraversion as a personality characteristic of studied nurses and four nursing competencies (P value < 0.05). Conclusion: This study helped to clarify critical care nurses level of competence; most of them have an expert level of nursing competency, and this study validated the importance of personality characteristics in the development of critical nursing competence. Recommendation: More studies are essential to assess the variables influencing critical care nurses' competency.