Purpose: The purpose of this study is to analyze the effects of organizational culture, transformational leadership and transactional leadership on organizational commitment, job commitment, and innovative behavior, which are variables for organizational effectiveness. Furthermore, the research explores the differences in the variables between civil and military hospitals. Methods: The subjects of the questionnaire survey were nurses from four mega civil hospitals and four military hospitals. Pearson correlation coefficient, factor analysis and hierarchial regression analysis were used for data analysis. Results: The results of the statistical analysis were as follows: Firstly, Clan culture (β=.574, p<.001, β=.363, p<.001, β=.166, p=.090) has a positive effect on organizational effectiveness(organizational commitment, job commitment and innovative behavior) while adhocracy culture(β=.332, p=.013, β=.331, p=.005) demonstrates positive effect on organizational commitment and innovative behavior. Secondly, transformational leadership(β=.288, p=.001, β=.160, p=.014, β=.173, p=.021) is positively correlated to organizational effectiveness. Lastly, transformational leadership has large positive effect on job commitment in the military hospitals (β=.433, p=.002). Conclusion: The study highlights that clan culture should be reinforced to enhance organizational effectiveness in both civil and military hospitals. Moreover, efforts should be made to develop transformational leadership particularly on job commitment in military hospitals.