Certain polymer materials, when electrically charged, exhibit a strong piezoelectric effect. Most prominent among these is polyvinylidene fluoride (PVDF) whose piezoelectric behavior was discovered only about a decade ago. In the present paper, the various change storage effects in PVDF and other polymers will be described, and the relation between the electrical polarization and the piezoelectricity discussed. The applications of these materials in electroacoustical and electromechanical transducers and in other devices will also be reviewed.