A method for location registration update on failure to insert subscriber data caused by a location registration error in a mobile communication system, comprising (a) in the case of a change in subscriber data, a home location register transmitting the subscriber data to a first switching center in which location of a corresponding subscriber is registered, to request the first switching center to insert the subscriber data; (b) in the case of the first switching center's failure to insert the subscriber data, the home location register being notified of the failure; and (c) the home location register extracting a switching center group, to which the first switching center belongs, from a switching center group database for storing switching center data that is grouped according to geographical closeness, and transmitting a location registration update request signal to switching centers in the extracted group.