A mobile object tracking system is provided for tracking the removal and use of specific objects within a group checked out from storage between the time the objects are checked out and the replacement of the objects in the storage. The system includes a system controller and a storage unit that receive and store a series of object carriers therein. Each object carrier includes a series of object holders in which id tags for the group of objects checked out of the storage are received. The object carrier monitors the time each object is removed from the object carrier, which information is thereafter communicated to the system controller.