This paper presents the result of a primary research which occurred in a sample of Greek teachers. The aims was to investigate whether the demographics were a factor which affects job stress and operates as a mediator. The research occurred in a sample of 208 primary education teachers. The adaptation to the Greek version of TSI for this research has been used, as it has been made by Agagiotou (2011). The outcome of the research indicated that demographics determine the levels of job stress. Especially factors such as age and teaching experience are moderators. Years in this school unit also varied responses to overall anxiety and also to the dimension of personal stress at work. The working relationship affected the dimensions of lack of control and good control at work, the marital status affected the lack of control, and the education affected the aspect of having a fair control at work”. The paper makes a recommendation for future research.