Background : Androgens stimulate the growth of hair in various are of skin including the pubis, axilla and beard, whereas in the scalp androgens promote baldness in genitically predisposed individuals. Androgens bind to specific intracellular receptors, which modulate saecific gene expression and so affect hair loss. Androgenetic isldness is first apparent on the frontalegion, with recession of the hair line. As this progresses, aloperia also develops on the vertex. But the osterior and lateral scalp area is spared, even in the most advanced eases, and even in old age. Objective : The purpose of our study is to find out the difference of androgen receptor expression in lesional and non lesional scailp of androgenetic alopecia patients by iminunohistochemical staining. Methods : Biopsy specimens were taken from its lesion(vertex) and its non lesion(occiput) of 3 patients with androgenetic alopecia and 4 normal controls. The deteatic n of androgen receptor was performed by an immunohistochemical technique(streptavidin peroxidasc method) using monoclonal antibody against androgen receptor. Results : Androgen receptors were strongly expressed in eccrine land and sebaceous gland, and weakly expressed in epidermal cells, hair infundibulum, hair bulb epith-lium and dermal hair papilla. Conclusion : There was no significant difference of the expression if androgen receptors in lesional and non lesional scalp of androgenetic alopecia. (Kor J Dermatol 1994;32(5):848-852)