Abstract: A method is suggested for the simultaneous personalization of several portable data carriers (2) respectively having at least one integrated circuit (6) for storing and/or processing information. According to the invention a unidirectional protocol serves for transmitting an identical personalization signal to several portable data carriers (2). These detect personalization data on this basis and store them in the integrated circuits (6). Preferably adapter elements (100; 101; 102) are used, which can accommodate at least one data carrier (50) and which are equipped with first interfaces (140; 150) for communicating with a reading device (20; 21; 22) and with second interfaces (120) for communicating with the accommodated data carrier (2). In a variant the portable data carriers (1) are transported in a transport device (600) which, at least temporarily, electrically contacts the contact area (9) of the portable data carriers (2) by means of a contacting unit (604).