Eight polyethylene-matrix composites with 4 mineral fillers were 2-stage extruded to 1.5 mm thick films oriented then by tension 10-120 kPa. The films were corona discharge-treated and studied for piezoelec. properties. The piezoelec. charge was stable for 200 days but the piezoelec. coeff. was smaller than in the case of polarization in the elec. field.