The importance of immunohistochemistry (IHC) to our understanding, ability to confidently diagnose and treat Kaposi's sarcoma (KS) has grown steadily in the past few decades. IHC has been performed on many KS specimen types, with > 100 different primary antibodies. Therefore, it is not surprising that IHC has helped unravel the histogenesis, understand the pathogenesis and facilitate the diagnosis of KS and identify novel therapeutic targets in the disease. This paper reviews the literature on the use of IHC in the study of KS.