This chapter briefly presents a various industrial applications of real-time simulation in the fields of power systems, motor drives, avionics and robotics. It also presents the model-based design methodology, and discusses the main challenges encountered in the design of real-time simulators (RTS). The most important aspect of real-time simulation technologies is that they need to make their computations fast enough to keep up with real-world time. Modern RTS are typically built around multicore multiprocessor PCs with extensive I/O capabilities based on field programmable gate array (FPGA) technology. The chapter discusses various applications of real-time simulation. These applications are: rapid control prototyping (RCP), hardware-in-the-loop testing (HIL) or controller-in-the-loop (CIL), software-in-the-loop (SIL), power-hardware-in-the-loop (PHIL), and rapid simulation (RS). The FPGA models are also integrated into the RT-LAB real-time environment and directly linked with the simulator I/Os, providing ultra-low HIL gate-in-to-current-out latency, suitable for testing motor controllers with ultra-low latency requirements.