Abstract: A method for memory management in a mobile device, and a mobile device for performing the method, are provided. The mobile device performs garbage collection in a flexible manner after transitioning from the sleep state to the wakeup state according to the paging cycle. This contributes to securing the sleep interval for the mobile device and reducing power consumption. The memory management method includes transitioning from a sleep state to a wakeup state, performing a paging procedure in the wakeup state, determining whether to initiate garbage collection after completion of the paging procedure, performing, when it is determined that garbage collection is to be initiated, garbage collection according to a paging cycle, and transitioning from the wakeup state to the sleep state after completion of garbage collection.