In vitro grown class II-MHC antigen free epidermal sheets were used as epidermal allografts (EAG) across a major histocompatibility barrier in 20 non-immunosuppressed recipients suffering from leg ulcers. Class I antigens were expressed on cell membranes of basal cell layer only on the epidermal sheets. After grafting, patchy areas of membrane fluorescence were observed among cells from the suprabasal layers on the epidermis from skin biopsies taken between days 5 and 28. All cells of the basal and the suprabasal layers expressed class I antigens on biopsies taken after day 28, as on normal human epidermis. This work demonstrates that class I antigens are expressed by epidermal cells in cultures used for grafting. The absence of rejection cannot be explained by the absence of class I-MHC antigens in EAG.