This study aims to consider the relationships between job fatigue, organizational citizenship behavior and organizational atmosphere. The evaluation of each variable is a kind of decision making problem which has systematic transaction between variables. So, Decision making trial and evaluation laboratory (DEMATEL) is suitable for defining the cause and effect relationships between variables. We can use this method as a way for managing interdependencies in a set of variable. This study has applied the ideas of 10 experts and specialist of human resource management in Iran-Khodro Diesel. The results showed that job fatigue effects on organizational citizenship and organizational atmosphere, organizational atmosphere effects on job fatigue and organizational citizenship behavior, organizational culture effects on job fatigue, organizational citizenship behavior and organizational atmosphere. On the other hand, organizational citizenship behavior is the most impressible and organizational culture is the most effective variables.