A system is provided for detecting moisture at an absorbent article. The system includes a device arranged to be attached on the absorbent article and a resonance circuit including a moisture sensitive part, wherein the resonance circuit has a first resonance frequency when the moisture sensitive part is in a dry condition and a second resonance frequency when the moisture sensitive part is in a moist condition. The system further includes a monitoring unit being arranged to transmit a test signal to the device, receive a response signal from the device, determine a frequency of the response signal and generate a detection signal if the determined frequency corresponds to the second resonance frequency. There is also provided a method for detecting moisture at a device attached on an absorbent article.