In the current international investment system, although most of the states have voluntarily accepted some restrictions on their sovereignty in order to participate in international economy, they have created a powerful tool to ensure their authority and sovereignty in sensitive cases, in order to protect the fundamental basis and principles of their countries. This contractual device is the anticipation of exception clause related to preservation of essential interests of the host state of investment. For instance, in investment maters, with the aim of providing a stable and predictable environment for foreign investors, governments conclude bilateral or multilateral treaties. Such treaties, by predicting various rights for investors, to a large extent constrain the sovereignty domains of the host state of investment on the one hand, they contain a clause known as exception clause, dealing with, generally, protection of essential interest of the host state such as, its critical economy situation, security, public policy, and the like, on the other hand.Despite the growing trend for inclusion of such an exception in international investment agreements and treaties, especially bilateral investment treaties of promoting and protecting foreign investment, Iran except in very rare cases, has failed to include such a condition in its investment treaties. Hence, this article intends to review and analyze this subject, to clarify its importance for practitioners and designers of treaties related to investment in Iran and to provide a guideline for its recognition. For this purpose, in addition to investigating this exception condition in the practices of international investment agreements and international cases, the verdicts issued in Argentine cases in its financial crisis, is an appropriate opportunity to review this condition in practice, which have been studied in this article.