Background: Nowadays organizations are operating in a highly competitive global environment. Therefore, managers use different mechanisms such as downsizing of organizations, automation of works for promoting productivity of their organizations.Although these mechanisms are useful but one of the most important factors is committed and qualitative human Resources. During recent years ORGANIZATIONAL citizenship behavior (OCB) has been considered an effective factor in gaining employees commitment to the organization and relatively considerable researches have been focused on identifying effective factors for nurturing these behaviors. As a result, common factors such as contextual variables (group norms, ORGANIZATIONAL structure and culture) were identified for development of OCB. In this article, impact of employees’ impression of ORGANIZATIONAL JUSTICE on OCB in the National Iranian Oil Products Refining & Distribution Co was studied.Methods: in terms of purpose, the research method is applied and in terms of data collection, is descriptive- survey. In this article, ORGANIZATIONAL JUSTICE, including four dimensions (distributive, procedural, interactional and informational JUSTICE) and their impact on nurturing OCB, from employees' point of view, was investigated. Data were collected from employees of foregoing corporation and hypotheses were investigated by binominal test.Results: The results showed that employees’ impression of ORGANIZATIONAL JUSTICE including foregoing four dimensions, have impact on OCB. In ranking these dimensions interactional JUSTICE is first, distributive JUSTICE is second, informational JUSTICE is third and procedural JUSTICE is the last.Conclusion: Based on these results, it can be concluded that OCB can be influenced by employees’ impression of ORGANIZATIONAL JUSTICE.