The topic of this thesis is a commercial loan agreement. Given that this is a commercial contract, the first part of this paper will first begin with a presentation of the basic concepts of commercial law, and the specifics of commercial law by which it differs from civil law and their relationship. The preconditions that the contract must meet in order to apply the commercial law will be stated, with the indication of the relevant regulations which lead to the classification of the contract as a commercial one. Despite the differences between commercial and civil law, there is a close connection between them which will be explained and it will be stated in which regulations the rules of commercial law are contained and what role they play in contracting, concluding and fulfilling contracts in general. After a detailed consideration of commercial law, its specific rules and the order of application of sources to a commercial contract, the hierarchy of sources applicable to the loan agreement will be presented depending on its character as a commercial, civil or consumer contract. By presenting the hierarchy of sources of the trade loan agreement, an example of the said agreement and general business conditions will be presented. The main part of this paper elaborates the relevant rules of our legal system that are provided for a civil loan agreement, stating certain specifics in the case of a commercial loan agreement. Therefore, the relevant provisions of the law on the loan agreement, their correct interpretation and finding appropriate solutions in the law when not negotiating certain issues that may arise in the contractual relationship between the bank and the merchant will be presented in detail.