The subject of the bilateral guaranty, its transference manner, and its time, has long been manifested in the Shiite jurisprudential texts in terms of transactions, and has been completely explained from the beginning. The domestic laws of Iran are also influenced and are in accordance with its rules. What is important of note in the current study is that it deals with the position of bilateral guaranty in 1980’s Vienna Trade Convention, which knows itself as the pioneer and inventor of a new solution to solve the problems caused by the breach that may occur during a transaction. In this regard, it is bound to investigate the concept and bases of the guaranty, and explain the differences and similarities between the domestic law and the convention, which finally leads to clarification of the conformity of the rules of the convention with the rules of domestic law of Iran, which is also directly derived from Shi'i jurisprudence.
