The main hypothesis of this article is that these two countries' approach toward the structure of international system and resulting policies toward this structure have played a pivotal role to initiate and terminate the war. The authors mainly argue that Iran's critic approach toward the structure of international system and its efforts to destroy such a structure opposed by Iraq's cooperation with international system and its efforts to take advantage from this system to maximize its power have played an influential role in the initiation of war. Therefore as long as such a doctrine dominated the decision-makers and foreign policy of both countries, the war continued. However, when political, economic, military and consequent disruption of power balance against Iran started and Tehran's approach toward the structure of international system was adjusted, the war terminated.