Since the documentary credits were the most widely used in the field of international commerce, as to ensure the execution of international sales contracts, the question, of the legal nature of the two categories of documentary credits : Simple (which did not stipulate to be transferable) and the transferable one, is extremely important. To illustrate the special nature of documentary credit, it is necessary to differentiate between the documentary credit simple and other similar operations: as letter of guarantee, standby Credit and documentary collection, and between the transferable documentary credit and the other similar operations as assignment of right, back to back credit and other specific credits.