Immunohistochemistry (IHC) is a technique that allows the localization of antigens or proteins in tissue sections using the high specificity and affinity of antibodies to recognize molecules and join them. The commercial offer and the standardization of protocols make this technique a simple, fast, and powerful method. Microglia, the resident macrophage cells of the central nervous system, can exist in three different forms that can be identified using different antibodies. The aim of this chapter is to describe the methods to perform IHC using these different antibodies.