Hall voltage and conductivity of semiconducting CdS crystals with different mobilities have been measured at high pulsed electric fields. The electron density is nearly constant in a wide range of field which includes the field of current saturation. At fields above 2.1 × 103V/cm, electron multiplication due to impact ionization is observed. In the case of an electric field parallel to thecaxis of the crystal, the Hall drift velocity at the saturation field is determined by the interaction of electrons with off‐axis shear waves of sound.