Background: Job satisfaction and its effective factors are important issue in productivity improvement. The main purpose of this study is to determine the job satisfaction of nurses in pre-hospital and hospital emergency rooms of Mashhad health system. Materials and Methods:The present study was descriptive-analytic with cross-sectional design carried out on nurses working in 168 pre-hospital emergency bases and 12 emergency departments of public hospitals of Mashhad affiliated to Mashhad University of Medical Sciences in 2017. A total of 232 nurses working in pre-hospital and hospital emergency units were selected and studied. A reliable and valid questionnaire including personal and professional information was used for collecting data based on the standardized Brayfield and Ruth Job Satisfaction test. Data analysis was performed by 1-sample t test, 1-way t test, two Independent samples, and linear regression analysis in SPSS V. 18. Results:A total of 232 nurses answered to questionnaires. The average quality level of job satisfaction based on Brayfield and Ruth test was 62.6% in pre-hospital emergency nurses and 62.4% in nurses of emergency hospital. It was also found that the variables of age, gender, educational level, service record, working hours, income level and marital status were significant determinants of job satisfaction, so that these variables were altogether explain about 30%(F=13.5, P<0.001) of job satisfaction. Conclusion:Based on the findings of this study, nurses' workplace is not associated with their job satisfaction. Also, job satisfaction is affected by many demographic variables, which change due to time and place and social conditions.