Motivated and efficient human resources have a very significant role in increasing the effectiveness of an organization. Knowing the rate of employees’job satisfaction may help the managers to improve human resource productivity. Based on different studies, there are a lot of Factors inFluencing job satisfaction. The rate of influence of each factor is different depending on the size, culture, awarding system, promotional system, kind of production and other environmental factors of an organization. In this research, based on scientific hypotheses and tests, it was tried to obtoin the main determinants of job satisfaction in public sectors. According to a case study in Interior Ministry, it was found out that which factors for the dependent variable of job satisfaction have a predictor role and which of the independient variables such as appraisal system, leadership style, level of income and promotional system has a significant relation with it.