This Review Article examines the potential of spintronics in four key areas of application -memories, sensors, microwave devices, and logic devices - and discusses the challenges that need be addressed in order to integrate spintronic materials and functionalities into mainstream microelectronic platforms. Spintronic devices exploit the spin, as well as the charge, of electrons and could bring new capabilities to the microelectronics industry. However, in order for spintronic devices to meet the ever-increasing demands of the industry, innovation in terms of materials, processes and circuits are required. Here, we review recent developments in spintronics that could soon have an impact on the microelectronics and information technology industry. We highlight and explore four key areas: magnetic memories, magnetic sensors, radio-frequency and microwave devices, and logic and non-Boolean devices. We also discuss the challenges-at both the device and the system level-that need be addressed in order to integrate spintronic materials and functionalities into mainstream microelectronic platforms.