Abstract: A priority based protocol for a two-way paging system improves the life expectancy of the pager's battery by minimizing use of pager's transmitter, without significantly impacting the reliability of the system or the timeliness of message delivery. This is accomplished by eliminating the need to always sends acknowledgments of received messages and by piggybacking acknowledgments and messages together in a single transmission. In the priority based protocol, high priority messages are immediately acknowledged by the pager. All messages include a message sequence number. When a non-critical message is received by a pager, it checks the message sequence numbers of earlier messages to determine whether an earlier message is missing. If so, the pager sends to the paging network a request to resend the missing message.