The study of lien in United Nations Convention on Contracts for the International Sale of Goods as well as assaying Iranian law on commerce and the principle of speed in commercial transactions are of importance. One can add to them the unification of the laws related to sale in various countries which is pursued by the legislators. United Nations Convention on Contracts for the International Sale of Goods seeks to establish an international economic order to tackle the legal impediments of international transactions. Given the development of the subject many countries have joined this convention until now. In commerce principle of speed in commercial transactions is of paramount significance. Unification of laws related to sale in various countries is one of the key concerns of the legislators. United Nations Convention on Contracts for the International Sale of Goods is an effort for preparing the ground for a better future for the international sales of the signatories. According to this convention, delivery of good and paying the price, provided an agreement has been reached between the parties of the time of payment of the price and/or the delivery of the good, are mutually required and the good and documents should be delivered to the buyer and the seller can make the performance of obligations conditional upon the payment of the price by the buyer.
