The idea of crediting and credit repayment is based on an assumption that each payment of the principal reduces the debt balance. This tendency is not followed in case of the hypothecary credit al-lowed and paid out in PLN and indexed to Swiss franc. Here, the balance of principal repaid in PLN is a function of currency exchange rate fluctuations. The situation denies then the idea of credit, according to which “you pay back as much as borrowed”. The cost of credit, calculated as a total of the LIBOR – credit in CHF (WIBOR – credit in PLN) rate and the bank’s margin specified in the contract. The purpose of the paper is to prove that a banking product like this does not meet the standards of crediting, the principal balance being dependent ...