Abstract: A method of effecting automatic callback in a mobile telecommunication system. A calling subscriber is permanently connected to a public switched telephone network and a called subscriber is a mobile unit which moves in the public land mobile network. A centrally located home location register keeps an account of where all mobiles registered in the mobile telecommunication network are located, with the aid of local databases, so-called visitor location registers. The called subscriber calls the called subscriber and finds that the subscriber is busy. The calling subscriber then dials a code, wherewith a reference is stored in a queue in the home location register, this queue relating to the called subscriber. When the called subscriber is free to receive a call, the calling subscriber is informed to this effect. The calling subscriber then lifts his telephone receiver and a connection is set-up between the two subscribers. When the called subscriber answers, the call is considered to have been connected.