The example of RFID systems examines the data protection legal requirements for the use of auto-ID procedures under the conditions of Ubiquitous Computing. Differentiated by functional areas of the RFID front-end and RFID back-end systems, the author explains the conditions and challenges related to data handling processes, accountability, legality criteria, special transparency requirements, and the rights of affected individuals. In doing so, the limits of the applicable data protection law are explored, and approaches for its further development are discussed against the backdrop of an increasingly digital world.