Background: Nursing and other health care jobs will be challenged to respond the changing needs of people and changing nature society; this requires that nurses accept managerial roles to manage and support nurses’ needs for continuing professional development. This study was developed to investigate the relationship between commanding leadership style and personality traits of nursing managers of hospitals affiliated to Tehran Medical Sciences Universities.

Materials and methods: In this descriptive- correlational study, 140 nurse managers affiliated to hospitals of Tehran Medical Sciences Universities were selected by multi-stage sampling. The data collection tools were three standard questionnaires, including leadership style, personality traits and demographic properties. The Cronbach's alpha reliability were calculated for leadership style questionnaire as 0.86 and personality traits as 0.88. Data were analyzed by spss19 using descriptive and inferential statistics.

Results: Most nurse managers had commanding leadership style and personality traits of conscientiousness There were significant inverse relationship between commanding leadership style and extraversion, openness, Adaptability and also conscientiousness personality traits (P<0.05).

Conclusion: By the personality traits score, it may be predicted leadership style of a manager's future; it is a proper way to select persons with more effective leadership style and optimization management organization.

Keywords: Commanding leadership style, Personality traits, Nurse managers.