A location service-providing system and a method for providing a deferred location request service by using previously computed position estimates. In the system and the method, if an H-SLP transmits an SUPL INIT message including location information to a target SUPL Enabled Terminal (SET) according to a location service request from an SUPL AGENT, the location information including at least one of a previous position estimate and previous assistant data, the target SET receives the SUPL INIT message, determines whether it is possible to provide the location service by reusing at least one of the location information in the SUPL INIT message and previously stored location information, when it is possible, determining position information by reusing at least one of the location information in the SUPL INIT message and the previously stored location information, and providing the SUPL AGENT with the position information.