A secure document receptacle for use in file cabinets having slidable drawers with laterally spaced support rails for removable supporting file folders. The secure document receptacle has a single support brace along the top edge with downwardly opening channels for removable engagement with the drawer support rails. The receptacle has a closed top edge and openings to the interior of the receptacle on the side edge or the bottom edge of the receptacle. Documents can only be inserted and removed via the open side or bottom edges. The receptacle must be partially or completely removed from the drawer support rails before a document can be removed from the receptacle. This interrupts contact between the brace channels and the support rails, an event which can be detected by cabinet sensing circuitry.