OBJECTIVE To study the incidence and prognosis of immunologic rejection of the central graft after limbal allograft transplantation (keratolimbal allograft transplantation [KLAT]) combined with penetrating keratoplasty (PKP). METHODS Endothelial rejection in central penetrating graft after simultaneous KLAT and PKP using the same donor cornea was retrospectively studied. Incidence, reversibility, prognosis, and changes in limbal grafts were examined. RESULTS Forty-five eyes underwent simultaneous PKP and KLAT. Endothelial rejection of the central graft was found in 16 eyes (35.6%). At last examination, 10 grafts (62.5%) restored clarity after immunosuppressive therapy. During rejection episodes, four eyes showed engorgement of vessels in limbal grafts, which existed before the episodes. Only one eye developed neovascularization with mild edema of the limbal grafts; however, no other limbal grafts showed abnormalities on biomicroscopy. No epithelial changes were noted, and 14 grafts (87.5%) were covered by corneal epithelium after the rejection. CONCLUSIONS Approximately one third of eyes had endothelial rejection in the central graft after simultaneous KLAT and PKP. Abnormalities suggestive of rejection in the limbal grafts were seldom observed in these eyes, suggesting that immunologic response was different in central and limbal grafts.