Immunohistochemistry is an important technique that uses specific antibodies to determine the cellular localization of proteins/antigens in highly complex organs and tissues. While most immunohistochemistry experiments target protein epitopes, nonprotein antigens including BrdU may also be detected. Briefly, tissues are fixed, processed, sectioned, and then probed by a primary antibody while preserving the integrity of the tissue and cellular morphology. There are various methods available for visualization of the bound primary antibody that involve a reporter molecule which can be detected using light or fluorescent microscopy. Here we describe a basic immunohistochemistry protocol for identifying protein localization in testis sections using protein-specific antibodies.