A set of nonlinear electrothermoelastic constitutive relations was derived to represent the electric hysteresis effects in a piezomaterial by following a consistent thremodynamic formulation. The field of smart structures has got great importance in the field of research with the development of piezoceramic sensors and actuators of different shapes and sizes for the use in structural applications. Piezomaterials has showed polarization-electric (P-E) field hysteretic losses under cyclic variation of the applied electric field. It was observed that the area of the P-E hysteresis loop decreases with an increasing compressive preload. Experimental data showed that as the preloading increases, the remnant polarization shows a reduction in magnitude.The nonlinear electrothermoelastic formulation can also be easily integrated in the structural dynamic analysis of smart structures with embedded piezoactuators and sensors.