A method for interrogating a passive sensor comprising at least one piezoelectric resonator includes the following steps: the identification of the characteristic width of the resonant frequency band of the resonator; the determination of a scan interval equal to a third of the measured bandwidth; a first series of three interrogation measurements with signals respectively at a first frequency, at a second frequency and at a third frequency making it possible to define a first resonance value, a second resonance value and a third resonance value; the determination by a parabolic fitting operation of the resonator response curve on the basis of said first, second and third resonance values, so as to calculate a first value of the frequency in real time of the resonator. The invention also relates to an electronic device for interrogating a passive sensor comprising at least one piezoelectric resonator and comprising a micro-controller implementing the interrogation method of the invention.