This article deals with the definition, types, benefits in international trade, legality, and steps of initiating and executing Letter of Credit (LC). It discusses the questions raised about the conformity of some types of LC with the principles and criteria of Islamic law and the way to address issues related to its illegality. The article surveys the applications of LC in Islamic banks, which are based on the contracts of murabahah, mudarabah, musharakah and wakalah. It was concluded that LC can be legal in Islamic law as long as it does not involve both form and spirit credit based on usury/interest, but a financing based on real murabahah, mudarabah, musharakah and wakalah.