A semiconductor device with an integrated circuit on a semiconductor substrate comprises a Hall effect sensor in a first active region and a lateral high voltage MOS transistor in a second active region. The semiconductor device of the present invention is characterized in that the structure of the integrated Hall effect sensor is strongly related with the structure of a high-voltage DMOS transistor. The integrated Hall effect sensor is in some features similar to a per se known high-voltage DMOS transistor having a double RESURF structure. The control contacts of the Hall effect sensor correspond to the source and drain contacts of the high-voltage DMOS transistor. The semiconductor device of the present invention allows a simplification of the process integration.