The main objective of this paper is to point out the significance and importance of understanding a foreign currency clause in banks. This paper analyses the basic characteristics and the purpose of a foreign currency clause and the impact of its use on the monetary system of the Republic of Croatia. By analysing the use of foreign currency clauses in Croatia it can be concluded that in the past it existed because of the unstable currency. The currency clause was used as a protection from risk for the counterparties. The results of the secondary research show an unjustified use of the currency clause in Croatia after the introduction of kuna as a legal and final means of payment because it stands out as one of the most stable world currencies in the past years. The results of the current case "Franak" suggest that the state did not immediately use its mechanisms to protect its citizens that were debtors with a loan in the foreign currency of the Swwis franc, which differs to Hungary that stood up in defence of its citizens right away. The Republic of Croatia reacteda bit late withtheir mechanisms. The blame for the case of "Franak" carry the banks because they did not warn the citizens about the risks arising from loans indexed to the Swiss franc. Moreover, the citizens have not thought about the potential dangers but were attracted by the low cost of such loans. In addition, there has been insufficient warnings on the behalf of regulators about the risks associated with loans in the "Swiss". They could have limited such loans. All participants: citizens, banks and regulators could be held responsible for the "case franc" and should bear the consequences.