Merchandise security systems and methods are provided. In one example, a merchandise security system includes a plurality of electronic keys and a plurality of merchandise security devices located within a retail store. Each electronic key and each merchandise security device is configured to store one or more serial numbers. In addition, each electronic key is configured to be authorized for communication with one or more merchandise security devices within the retail store. An electronic key is configured to communicate with a merchandise security device for locking, unlocking, arming, and/or disarming the merchandise security device when the serial numbers match.