Rabbits immunized with full-thickness human fetal skin developed circulating antibodies against antigen (s) in human epidermis. The antisera reacted with a common antigen in human esophagus and ileum but did not cross-react with tissues or serum obtained from other species. Evidence of the development of delayed hypersensitivity to antigens of human epidermis was equivocal. No cutaneous or visceral lesions developed in the animals studied during a 15-month period of observation.