Purpose: The purpose of this study was to analyze the paths of influence that a hospital’s ethical climate exerts on nurses’ organizational commitment and organizational citizenship behavior, with supervisor trust as the mediating factor, and verify compatibility of the models in hospital nurses. Methods: The sample consisted of 374 nurses recruited from four hospitals in 3 cities in Korea. The measurements included the Ethical Climate Questionnaire, Supervisor Trust Questionnaire, Organizational Commitment Questionnaire and Organizational Citizenship Behavior Questionnaire. Ethical Climate Questionnaire consisted of 6 factors; benevolence, personal morality, company rules and procedures, laws and professional codes, self-interest and efficiency. Data were analysed using SPSS version 18.0 and AMOS version 18.0. Results: Supervisor trust was explained by benevolence and self-interest (29.8%). Organizational commitment was explained by benevolence, supervisor trust, personal morality, and rules and procedures (40.4%). Organizational citizenship behavior was explained by supervisor trust, laws and codes, and benevolence (21.8%). Conclusion: Findings indicate that managers need to develop a positive hospital ethical climate in order to improve nurses’ trust in supervisors, organizational commitment and organizational citizenship behavior.