A method for minimizing the access delay in wireless communication systems, e.g. GPRS (General Packet Radio Service) networks, which includes at least a base station system and at least a mobile terminal having a communication context with the GPRS network. The above mentioned mobile terminal is also adapted to open a communication with the radio access network of said base station system to initiate a Temporary Block Flow or TBF establishment each time has to transmit data packets to the network and the TBF is released when the transmission of the packet has been completed. The TBF establishment is requested by means of a Radio Link Control message or RLC called Packet Channel Request or PCR sent on one of the Control Channel of the GPRS radio access and in particular on the Packet Random Access Channel or PRACH. The GPRS data packets and messages are organized in frame with a predetermined number of TDMA slots and in multiframe. According to the method, when the mobile has at least a Link Layer Control or LLC to transmit it send a PCR message on the PRACH and said PCR message is transmitted in a TDMA slot randomly selected on the TDMA slots that compose the first PRACH block.