The purpose of this study was to analyze the role of job insecurity on the fatigue of sports boards staff in Isfahan province with the mediating role of psychological contract breach. The research method was structural correlation in nature and conducted through a survey. The statistical population of this study included the staff of Isfahan province sports boards. According to Morgan's Table, 225 people were selected as the research sample. In order to collect data, standard questionnaires of job insecurity by Peng et al. (2015),work fatigue by Frone and Tidwell (2015),and psychological contract breach by Tayong Mimba (2019) were used. The validity and reliability of the questionnaires were confirmed(Cronbach's alpha coefficient of the questionnaires was 0.81, 0.85, and 0.86, respectively). Statistical tests, including structural equation modeling, and PLS software were used to analyze the data. The results of the study showed that there is a positive and significant effect between job insecurity on employee fatigue(r=0.40), job insecurity on psychological contract breach(r=0.62),and psychological contract breach on fatigue(r=0.55) in the sports boards of Isfahan province. Also, the results confirmed the existence of a significant and positive effect of job insecurity on the fatigue of Isfahan's sports staff with the mediating role of psychological contract breach(r=0.34). Then, it was suggested that sports boards use positive longer contracts and provide conditions for the implementation of their psychological contracts, both in the field of work and work environment and compensation services to improve positive attitudes and feelings to employees Experience less job fatigue.