One of the original and exceptional institutions of the negotiable instruments law is the unjust enrichment case. Although unjust enrichment is regulated in the Turkish Code of Obligations in general terms and is accepted as a source of debt relations, it also constitutes the subject of a case-specific to the Turkish Code of Commerce and only negotiable instruments as a result of the choice of the legislator. Due to its exceptional nature, the legislator has also strictly determined the conditions that must be fulfilled to file an unjust enrichment case in negotiable instruments. This approach of the legislator is correct. The unjust enrichment case in negotiable instruments creates an extraordinary and additional demand opportunity for the right holder. Despite this option and opportunity, these bills are used only as ordinary bills instead of filing a lawsuit for unjust enrichment in negotiable instruments. Undoubtedly, this is a contradiction. To put it briefly, the reason for this contradiction is the lack of awareness in the practice of law.