Abstract: In this paper, Langerhans' cells(LC)is the lesions and normal-appearing skin adjacent to the esioas of 8 patients with psoriasis vulgaris were studies both with ATPase method end monoclonal antibody OKT6 using direct immunofluorescence technique.The results were as follows: LC with dendritic processes were evenly distributed and mainly located in the midepidermis of normal skin as shown by both methods. In the normal dermis, only a few LC were demonstrated discretely with OKT6 method. LC almost disappeared in the epidermis of the lesions, and one or two LC with-out processes might occasionally be seen just like small fluorescent ring. No recognizable LC was found in the dermis. Authors nuggeat that LC mad be involved is the pathogenesis of psoriasis.