Background and Aim: in international sales of goods contracts, considering that the parties to the contract are far from each other, its implementation costs such as transportation costs, insurance, export and import licenses, goods inspection certificates, etc. the costs of contracts It is internal. The aim of this article is the comparative study of fundamental violations in the 1980 Vienna Convention and Iranian law.
Materials and Methods: This article is descriptive and analytical. Materials and data are also qualitative and data collection was used in collecting materials and data.
Ethical Considerations: In this article, the originality of the texts, honesty and trustworthiness are observed.
Findings: The findings showed that the 1980 Vienna Convention on the International Sale of Goods, strict conditions in Article 25, tried on the one hand to prevent the wastage of executive costs and to maintain and guarantee the survival of the contract from prevent its unnecessary termination and annulment, and on the other hand, in order to protect the rights of the injured parties, prevent undue losses due to the breach of the contract.
Conclusion: This new legal establishment has been successful and very efficient in achieving these goals. In Iran's law, especially the provisions of civil law, despite the explanation of the right of termination due to multiple options, unfortunately, the legal establishment of the fundamental violation that documents the right of termination has not been identified and defined at all.