Phosphate-buffered saline (PBS) soluble extracts of human epidermis and dermis from secretor donors contain products with blood group antigenic activity. The predominant blood group in a sample was the same as the red cell phenotype of the donor. H substance activity was present in all PBS-soluble products (from A, B and O donors). By gel filtration chromatography on a Bio-Gel A-1.5 m column; the epidermal and dermal PBS-soluble blood group substances fractionate in the void volume.