The invention relates to a touch screen system with a touch screen (400) comprising a transparent and electrically conductive surface (450) arranged to receive touches from users (UA, UB) of the touch screen system; and touch sensitive elements (420) arranged to detect the position of said touches on said electrically conductive surface (450). The touch screen system is further comprising a touch identification system (900) comprising at least two electrodes (EA-ED), at least one transmitting unit (910) connected to the electrically conductive surface (450) for transmitting an identifying signal to said electrically conductive surface (450), and at least two receiving units (900A-900D), each connected to at least one of said electrodes (EA-ED) for detecting said identifying signal when a user (UA, UB) simultaneously touches the electrically conductive surface (450) and an electrode (EA-ED) that is connected to the receiving unit (900A-900D).