D. W. Organ(1977) published a paper about the importance of Organizational Citizenship Behavior(OCB) in an organization. Since then, the studies of OCB have been continuously increased. As recent business environment has changed with rapidity and uncertainty, OCB for the improvement performance of organization should be more emphasized. Role behaviors of organization are divided into two parts such as in-role behavior and extra-role behavior. In recent, although the researches about extra-role behavior have been studied, they are still not sufficient. This study attempted to examine relationships between organizational culture, organizational commitment and organizational citizenship behavior, Sample was 193 employee engaged in hospitals of Pusan. In this study I chose four factor(affective, conservative, task and innovative culture) of organizational culture and three factors (affective, continuous and normative commitment) of organizational commitment and five factors(altruism, conscientiousness, courtesy, civic virtue and sportsmanship) with regard to organization citizenship behavior. The major findings of the empirical research are as follows ; 1. The Causal relation of dimensions of organizational culture and dimensions of OCB. 1) Affective culture has significant impact on courtesy, civic virtue of OCB. 2) Conservative culture has no significant impact on all of OCB. 3) Task culture has significant impact on conscientiousness, civic virtue, sportsmanship of OCB. 4) Innovative culture has no significant impact on courtesy, civic virtue of OCB. 2. The Causal relation of dimensions of organizational commitment and dimensions of OCB. 1) Affective commitment has significant impact on all of OCB. 2) Continuous commitment has no significant impact on all of OCB. 3) Normative commitment has significant impact on courtesy, civic virtue of OCB. In brief, though this study has several limitations in research design and methods, the results suggest that organizational culture of hospitals and organizational comitment of hospitals shows a strong relationship to the organization citizenship behavior.