免疫组织化学染色法是指在抗体上结合萤光或可呈色的化学物质，利用免疫学原理中抗原和抗体间专一性的结合反应，检测细胞或组织中是否有目标抗原的存在，此方式不只可以用来测知抗原的表现量也可观察抗原所表现的位置。只要是能够让抗体结合的物质，也就是具有抗原性的物质包括蛋白质、核酸、多糖、病原体等都可侦测。

免疫组织化学的优势在于专一性、灵敏度、简便快速以及成本低廉，所以广为医院采用，通常是借由特定的肿瘤标记来筛选癌症。免疫组织化学染色法对基础研究及预防和诊疗上都是相当重要的一个方法。

Immunohistochemistry (IHC) refers to the process of detecting antigens (e.g. proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno", in reference to antibodies used in the procedure, and "histo," meaning tissue (compare to immunocytochemistry). The procedure was conceptualized and first implemented by Albert Coons in 1941.