In addition to the will of the parties and objective criteria in determining the law applicable to the current relationships in the international letter of credit, the disciplinary rules are among the factors influencing in the determination of the law applicable to the said relations. In the current conditions of trade, especially in the international arena, it is observed that the relations of activists in this field have gone beyond the boundaries of private relations and certain considerations related to the public interest have also been imposed on these relations. In this situation, the judge or arbitrator in determining the applicable law to the current relations in the letter of credit, in addition to validating the will of the parties and the existing objective criteria, also pays attention to public interest. In determining the applicable law in cases where the will of the parties or the objective criteria of law of a country determine as an applicable law to the legal relationship, the disciplinary rules currently applying in other legal systems related to that legal relationship in the letter of credit should also be considered. Therefore, in determining the law applicable to a legal relationship, the judge or arbitrator prevents the law determined based on the will of the parties or objective criteria, ignoring the disciplinary rules of the countries related to that legal relationship.