This paper deals with the problem of load testing mobile device management (MDM) systems. MDM systems should cope with peak loads generated by hundreds and thousands of mobile devices at a time. It is too hard and expensive to test the capabilities of an MDM system with so many real devices operating simultaneously. A much more convenient approach is to use load testing software that emulates numerous mobile devices. We state a set of requirements for the software designed for load testing MDM server, and propose the architecture of a load testing tool. This architecture allows emulating the main mobile platforms (Android, iOS, Windows Phone) and can be modified to support new platforms or operating system versions.