To support the massive demand for mobile services third generation land mobile systems will be based on a new architecture concept and adaptive techniques. Moreover, these systems are expected to offer service quality comparable to that of fixed networks contemporary to their deployment. UMTS (universal mobile telecommunication system) is the developing pan-European concept for third generation mobile systems. The paper briefly overviews the requirements for and the emerging architecture of the UMTS as they appear at the transition between two RACE research phases and the beginning of dedicated standardisation activity in ETSI.