Background and Objectives: The University of Medical Sciences is one of the most important organizational justices of the giving service to the citizens and the main purpose of that is giving service and supplying citizens’ needs. The study of the ethical behavior of nurses of this organization and its affecting of organizational justices leads to offer better services.

Materials and Methods: This descriptive and correlation analysis was performed to assess the role of job stress as a mediator between organizational justices and the job ethics of nurses. According to statistics offered in 2015, the number of total nurses of Taleghani hospital Mashhad was about 400 persons, from which 200 person were selected using the sampling formula. The survey method and questionnaire were used to collect the information. Then the data were analyzed using AMOS statistical software. 

Results: The organizational justice improved the job ethic. Moreover, stress can be as a mediator in this relationship between organizational justice and the job improvement ethic.

Conclusion: The study showed that there was a relationship between organizational justice and job ethic of nurses. Therefore, organizational justice could lead to their job ethic. Beside the positive role of organizational justice in job ethic improvement, the job stress act as a mediator in this relationship in which the effect of organizational justice on the job ethics is more among the nurses with low stress.