IT has been proposed that the mammalian epidermal Langerhans cell is an epidermal equivalent of the cells of the reticulo-endothelial system, which are involved in binding and presentation of allergens in lymph nodes and the spleen^1,2. The demonstration that these resident cells are capable of binding various allergens and migrate to the lymph vessels and local draining nodes, indicates a major function in the afferent arm of the primary immune response^3,4 and has improved understanding of contact allergic hypersensitivity reactions. Much still remains to be discovered concerning the characteristics of the cell type, its reactivity with various antigens, and its relationship to other cells of the immune system. We show here that epidermal Langerhans cells react positively by immunofluorescence with antisera raised in rabbits against human B lymphoblastoid cell line membrane glycoproteins, which indicates the presence of Ia-like antigens on these dendritic cells.