Purpose: The purpose of this study was to investigate the impacts of psychological empowerment and transformational leadership on organizational commitment among hospital nurses. Method: The sample consisted of 279 nurses from 3 university affiliated hospitals. Data were collected with self-administered questionnaires and analyzed using Pearson correlation and hierarchical regression. Result: Transformational leadership has greater influence on organizational commitment for nurses. Psychological empowerment and three transformational leadership(charisma, individualized consideration and inspiration) has direct effects on organizational commitment. Psychological empowerment did not interact the relationship between transformational leadership and organizational commitment. Conclusion: The results imply that nurse managers should exercise transformational leadership and empowering behaviors for nurses to be committed in organization.