A seat belt warning system comprises a sensing system associated to a vehicle seat for sensing a seat belt related status with respect to the vehicle seat. A control unit communicates with the sensing system in order to generate a warning signal depending on the seat belt related status determined by the sensing system. The sensing system further comprises a resonant circuit and a modulation circuit, which is associated to the resonant circuit. The control unit comprises an electromagnetic induction transmitting circuit and an electromagnetic induction receiving circuit. The modulation circuit is capable of modifying an influence of the resonant circuit on electromagnetic coupling between the transmitting circuit and the receiving circuit in a specific way according to the seat belt related status, which enables the receiving circuit to deliver a signal depending on the seat belt related status to the control unit.