Piezoresistive properties of thick‐film resistors obtained with ink series supplied by different manufacturers have been investigated as a function of composition, structure, sheet resistivity, and applied strain between 0 and ±1000 &mgr; strain. The strain sensitivity of thick‐film resistors appears to be a strong function of the nature of the conductive grains and of the sheet resistivity of the paste; the results obtained suggest a dominant role of the tunneling effect in the conduction mechanism and in the strain sensitivity.