Background: Nurse competency is a critical issue that is important for nurses, their organizations and their patients and empowers nurses in their practice. Factors related to nurses’ competency level require further investigation. Purpose: To investigate how nurses assess their level of competency and the professional and clinical factors that influence it. Methods: A convenience sample of 204 registered nurses from an affiliated university hospital was approached. The data was gathered using the Competency Inventory for Registered Nurses (CIRN) questionnaire. The Pearson correlation coefficient, t-test and one-way ANOVA test were used to analyze the data. Results: The findings revealed that nurses’ perceived competency level is in the middle range. The findings also revealed statistically significant differences in the nurses’ perceived level of competency due to their level of education (p=0.012). Nurses who reported fair and objective annual evaluations rated their competency higher than nurses who reported unfair evaluations (p=0.014). Nurses who expressed an interest in nursing perceived their competency level to be higher than those who did not (p=0.006); nurses who did not change units perceived their competency level to be higher than nurses who did (p=0.012). Conclusion: Nurses’ perceptions of performance evaluation, rotations between units, educational level and interest in the nursing profession are all factors that must be considered in order to improve clinical nursing competency. Implications for Nursing: It is critical to educate nurses through basic and continuing education, with a focus on clinical nursing competency achievement and improvement. Keywords: Nurses’ competency, Competency, Clinical competency, Perception, Professional nurses, Jordanian nurses.