Purpose: The purpose of this study was to identify the effects of self-efficacy and empowerment on perceived organizational support and organizational citizenship behavior of nurses. Method: The subjects of this study were 327 nurses who were working at seven hospitals. The data were collected by structured questionnaire from Feb. 12 to Mar. 5 of 2006. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, and Stepwise multiple regression on SPSS/PC 12.0 program. Results: The mean score of self-efficacy was 3.75, empowerment was 3.68, perceived organizational support(POS) was 2.87, and organizational citizenship behavior(OCB) was 3.64. The POS had statistically significant differences according to position(F=3.207, p=.013). The self-efficacy and empowerment were positively correlated with POS and OCB. The self-efficacy(7.0%), meaning(8.5%), competency(12.4%), self-determination(1.9%), and impact(4.8%) explained 34.6% of the variance for POS. The self-efficacy(17.1%), meaning(1.0%), competency(2.8%), self-determination(3.2%), and impact(13.2%) explained 37.3% of the variance for OCB. Conclusion: The findings showed that self-efficacy and empowerment were important factors for enhancing POS and OCB in nursing organization. Therefore, the nurse manager must establish the strategies to improve the self-efficacy and empowerment of the nurses in order to promote the POS and OCB.