Sheets of ethylenediaminetetraacetic acid (EDTA)- separated epidermis were examined using scanning electron, transmission electron, and light microscopy; sheets were also examined after staining for adenosine triphosphatase (ATPase) activity. Staining was improved by longer incubation with EDTA and by elimination of Trismal buffer as a tissue rinse. EDTA-separated epidermis showed better retention of ultrastructural integrity when washed with phosphate-buffered saline. The ATPase staining procedures described in this present study are ultrastructurally specific for the Langerhans cell.