Abstract: An antitheft case for preventing packed compact discs from being stolen is disclosed. The antitheft case has a base part. A lock part slidably engages with the base part, thus forming a box-shaped and openable body in cooperation with the base part. A lock assembly selectively locks or unlocks the position of the slidable lock part relative to the base part. The antitheft case of this invention has a simple and compact construction, thus allowing manufacturers to easily produce such cases at low cost and allowing disc sellers to easily and effectively lay out the discs for sale within a limited area. The case is also reliably locked, so that it effectively prevents the packed compact discs from being stolen by any unauthorized persons.