In recent years, conventional silicon-based high-speed computing circuits became increasingly power-hungry due to the leakage currents and accelerated data traffic. Furthermore, numerous short-channel and quantum effects are emerging that affect both the manufacturing process and the functionality of today’s microelectronic systems-on-chip. Spintronic devices that take advantage of the electron spin are widely seen as the most promising solutions to circumvent the CMOS technology scaling threats. Given that they combine non-volatility with radiation immunity, speed, low power consumption, and quasi-infinite endurance, it is possible to use them in a wide variety of applications. In this chapter, spintronic phenomena, technology and hybrid (CMOS/MRAM) devices are presented as well as their use in processor domain (to replace parts of the memory hierarchy), hybrid logic, and reconfigurable computing.