A heterologous corneal endothelial transplantation was attempted using human endothelial cells and a Lewis rat penetrating keratoplasty model. Cultured human endothelial cells were seeded to a Lewis rat cornea, which was denuded of its endothelium. When grafted into the syngeneic Lewis rat, the graft remained clear for at least five days, and then became opaque and edematous because of immune rejection reaction. In contrast, corneas denuded of their endothelium became opaque and edematous immediately after transplantation. These results demonstrate that transplanted endothelial cells have enough antigens to induce rejection reaction even though they have the functional capacity to deturge the cornea.