Thirty-two burned or plastic surgery patients were grafted with allogeneic cultured epidermis on autograft donor sites. Two techniques, the indirect enzyme conjugated Staphylococcus Protein A assay with monoclonal antibodies against A or B blood group antigens and the polymerase chain reaction to detect a Y chromosome-specific DNA sequence, were employed to identify the presence of cultured epidermal allograft based on different ABO blood grouping or sex between donor and recipient. The methods have the advantage of high sensitivity and specificity in identifying the existence of allogeneic skin cells in grafts. The results indicated that the survival time of cultured epidermal allograft was prolonged up to 35 days. In addition, the intact coverage on some grafting sites may be composed of both host and donor origin cells, after about 3 weeks postgrafting.