Abstract: Two monoclonal antibodies (mAb), H₁₄ and H₁₉,were selected for detailed study since they were shown to give similar staining pattern for human epidermal cells to pemphigus vulgaris serum (Pab) by IIF. However, the antigen(s) recognized by mAbs and by Pab are probably not the same as suggested by the following: (1) No reciprocal blocking in immunofluorescence between them. (2) The binding of mAbs and Pab to human epidermal cells were affected differently by various conditions and agents. (3) H₁₄ and H₁₉ were shown to precipitate from surface-labeled human epidermal cells several proteins which are clearly distinguishable by SDS-PAGE to those precipitated by Pab. H₁₉ stained all stratified squamous epithelia and most epithelial cells, but not other human tissues. These newly identified cell-surface antigens by H₁₉ may be used as markers for the identification of human epidermal tumors.