A system and method of providing a prepaid subscriber service to a mobile subscriber in an integrated wireless telecommunications network having a circuit-switched portion and a General Packet Radio Service (GPRS) packet-switched portion. A prepaid subscriber class (PPSC) is stored in a home location register (HLR) and the PPSC is sent from the HLR to a serving mobile switching center (MSC) when the subscriber registers in the circuit-switched portion of the network. The PPSC is sent from the HLR to a serving GPRS support node (SGSN) when the subscriber registers in the packet-switched portion of the network. Also the PPSC may be sent from the SGSN to a Gateway GPRS Support Node (GGSN) in order to indicate that the subscriber is a prepaid subscriber. When the mobile subscriber begins a packet-switched data session the SGSN GGSN or both periodically send partial call data records (CDRs) to a prepaid center (PPC). When the mobile subscriber begins a circuit-switched call the MSC periodically sends partial CDRs to the PPC. The PPC calculates in near real time a new account balance for the prepaid subscriber. The current call is disconnected and prepaid services are stopped when the account balance is reduced to zero.