Abstarct: The fundamental role of human resources as the main driver of the organizations is endorsed by many experts. Human resource which is the most valuable capital and property can provide numerous benefits for organizations. In today's changing and challengeable world, one of the most important issues of organizational studies is to identify the factors may affect the organizational citizenship behavior. Given the importance of organizational citizenship behavior and considering the effect of spirituality and job satisfaction on employees' attitudes and behaviors, the current study is aimed at investigating the effect of work spirituality on organizational citizenship behavior considering the moderating role of job satisfaction. This study is an applied research in terms of purpose and is descxriptive-survey in terms of method. The statistical population is comprised of all the employees of Astan Qods Razavi in Mashhad city. According to the information obtained (autumn and spring, 2015), the number of employees is 1926 amongst which a sample size of 244 was randomly selected and studied by Cochran's formula. Research data was gathered by three questionnaires and was analyzed by SPSS and AMOS software. Content validity was confirmed by obtaining the opinion of supervisor and some other experts, and construct validity was confirmed by conducting confirmatory factor analysis. Research reliability was also confirmed by using the Cronbach's alpha. Research hypotheses were tested by structural equation modeling and hierarchical regression analysis (Cohen et al.'s test). After hypothesis testing, the path coefficient of 0.62 was determined for the first hypothesis (the effect of work spirituality on organizational citizenship behavior) and 0.35 for the second (the moderation of job satisfaction on the relationship between work spirituality and organizational citizenship behavior) which were statistically significant at confidence level of 0.95. Furthermore, research findings indicated that the effect of work spirituality on organizational citizenship behavior is strongest when the job satisfaction is high. Given these results, I order to improve the work spirituality and its effect on organizational citizenship behavior; organizations should pay more attention to issues related to employees' job satisfaction. It should be mentioned that the current study has considered the interpretation deficiencies of spirituality and organizational citizenship behavior and some related concepts were compared with religious teachings.