This study was to determine the mediator or moderator role of empowerment in the relationship between the head nurse's transformational leadership and organizational commitment as perceived by staff nurses.

Data was collected from 451 nurses in a tertiary hospital located in B city by means of structured questionnaires. Data was analyzed with descriptive statistics, Pearson's correlation coefficient and hierarchial multiple regression using the SPSS program.

Empowerment showed mediating effects between the head nurse's transformational leadership and organizational commitment as perceived by staff nurses. However, empowerment did not show moderating effects.

Nurses' perception of empowerment, the head nurse's transformational leadership and organizational commitment have a strong relationship. This finding suggests the importance of empowering nurses to increase organizational commitment.