Intercellular adhesion molecule-1(ICAM-1) is a cell surface glycoprotein and plays unimportant role in inflammatory response. During inflammation, ICAM-1 is involved in the interaction between leukocytes and endothelial cells. By binding to cellular receptors, such a leukocyte function associated antigen-1(LFA-1), ICAM-1 interacts between activated endothelial cells and inflammatory cells and finally leads the leukocytes to leave the circulation and move toward the inflammatory site. Cholesteatoma is characterized by an abnormal presence of squamous epithelium in middle ear cavity with heavy infiltration of inflammatory cells. In this study we wanted to know the possible roles of ICAM-1 in development of cholesteatoma by the use of monoclonal antibody to the ICAM-1 and immunohistochemical technique, to investigate and compare the expression of ICAM-1 on normal ear canal skin, attic cholesteatoma and extended cholesteatoma. In normal canal skin, ICAM-1 expression was restricted on the basal layer of epidermis and some keratinocytes of hair follicle. But ICAM-1 expression was markedly increased in both superficial and deep dermal layer with heavy cellular infiltration in the capsule of the cholesteatoma tissue. Many keratinocytes present above the basal layer of cholesteatoma showing papillary ingrowth were stained with ICAM-1. From the above findings, that the ICAM-1 expression could be upregulated in cholesteatoma and played some role in the development of cholesteatoma.