A method and apparatus for performing a location update based on mobility information indicating a velocity of a Mobile Station (MS), and a method and apparatus for using a timer for a location update in a wireless access system are disclosed. The MS transmits a deregistration request message requesting initiation of idle mode to a first Base Station (BS), receives a deregistration command message including paging group information from the first BS, the paging group information including a primary paging group Identifier (ID) and primary paging offset of a primary paging group allocated to the MS, and a secondary paging group ID and secondary paging offset of a secondary paging group allocated to the MS, and activates a paging group location update timer after moving from the primary paging group to the secondary paging group. The deregistration request message includes first mobility information indicating a velocity of the MS and the paging group information is set based on the first mobility information.