In this work we investigated the phenomenon of electrification of polymer melts during extrusion. A dedicated measurement apparatus has been built in order to measure the electrostatic charge Q induced by a polymer melt similar to those used in literature. The system consists of a Faraday cup connected to an electrometer and a digital acquisition system for acquisition and analysis. The electrification was measured on commercial PS grades which have different molecular weigth (MW). Each one has been extruded at different temperatures (T), velocities (v) and capillary geometries (L/D). According to the literature on the topic, results have been expressed in terms of volume density of electric charge QL (nC/cm3) of the extrudate. We acknowledged a strong effect of both T and L/D over QL. Keywords. Polymer melt, Electrification, Electric double layer, Faraday cup, capillary rheometry.