Abstract: A presence management system for a cellular-based Push-to-Talk (PTT) service. The PTT infrastructure obtains presence-relevant network status information from elements of the cellular network and of the overlying data network such as the home location registers (HLRs) of the mobile switching centers (MSCs) and the Authentication Authorization and Accounting (AAA) element of the data network. Additionally, the presence management system may communicate with other networked resources such as a Short Messaging Service (SMS) center, a Mobile Instant Messaging (MIM) server, a Multimedia Messaging Service (MMS) center, a BREW download server, or others, to obtain information about the activities of subscriber mobile phones that can be used to determine their presence. The presence management system operates in accordance with a set of configurable rules to update presence status and to provide PTT subscribers with presence status updates.