Documentary letters of Credit are one of the most important payment methods used to facilitate international trade by mitigation of different risks connected with business partner or his country. Letter of credit transactions are relatively complexed and contractual relationship are governed by international rules and national laws. The aim of this scientific study is to identify legal aspects of letters of credit, to describe the relationship between parties of the letter of credit transaction and analysis the basic legal rules and laws governing these transactions. We used mainly classical scientific methods due to its descriptive character. We used the method of structured observation, determining the fundamental principles – the autonomy of letter of credit and the strict compliance, method of specification or concretisation – identification of relationship between parties and abstraction – definition of general and essential information about international rules and national laws of some countries.