A calibration process for an SAW sensor of the differential resonator type incorporated in an assembly, the sensor having two resonance frequencies (f1, f2) which vary differently as a function of the value of a physical magnitude (G) of the assembly. The process comprises the steps of: establishing an averaged calibration function (FCmoy(G)), which relates the difference between the two resonance frequencies (Δf=f2−f1) and the physical magnitude (G), said average calibration function being obtained by averaging over a plurality of sensors of the same type (Δf=FCmoy(G)); determining the difference (Δf0Cap) between the two resonance frequencies of the sensor when the physical magnitude (G) corresponds to a predetermined value (G0); determining the deviation of the sensor relative to the averaged calibration function, in frequency or in terms of the difference between the value (GCap) furnished by the sensor and the predetermined value (G0); and determining a corrected value (Gcorr) to be furnished by the sensor, taking account of said deviation.