The aim of this final paper is to process and define bank guarantees under the Oblications act. According to the above, at the outset, the provisions relating to contracts for banking business will be explained,then the concept of bank guarantee will be defined, then they will enter into defining the concept of bank guarantee, legal nature of bank guarantees, contractual and legal relations, and types of bank guarantees. After that,contractual guarantees will be analyzed,their duration and biling deadlines, documents required for biling and disputes. Besides,rules for calling guarantees will be define, it will be defined rules for calling guarantees, their content and biling risks,payment obligation and required payment documents, the payment time, the transfers of rights and the relationship between the bank and biling authority, all in accordance with the Obligations Act. The guarantees in business practice will be explained in detail, and the advantages and disadvantages of bank guarantees will be specified and analyzed. At the end there will be an example of a bank guarantee form, and an example from case law will be enclosed.