The binding sites of Concanavalin A (ConA) and pemphigus antibody in tbe intercellular spaces of the human epidermis have been investigated. Extraction of human skin with phosphate--buffcrcd saline (PBS) and 70% e1hanol resulted in complete loss of the binding sites of 1he pemphigus antibody, whereas the extracted skin still retained its reactivity 10 ConA. Preincubation with more than 0.25 mg/ml of ConA with normal skin caused a reduction in the binding of pemphigus sera. However, prcincubation of pemphigus sera with normal human skin caused no inhibition of the subsequent binding of fluorescein-labelled Con A. These results indicate that Con A binding si tes might be related to, bur not identical with those of pemphigus antibody.