Objective: To investigate the ultrastructural changes of removed cultivated corneal epithelial transplants using scanning and transmission electron microscopy. Methods: Allocultivated corneal epithelial transplantation, using an amniotic membrane carrier, was carried out on 3 patients. The primary diagnoses consisted of 1 with acute-phase chemical burn, one with drug-induced pseudopemphigoid, and 1 with Stevens-Johnson syndrome. After a period of several months the transplants were removed from these patients because of graft opacities. The removed transplants were then prepared for examination by scanning and transmission electron microscopy. Results: In all 3 cases there was a similar pattern of findings: the amniotic membrane remained intact, although it had become partially vascularized and invaded by keratocytes. Inflammatory cells were present in the epithelial layer and within the amniotic membrane. Most of the amniotic membrane was covered by conjunctival epithelial cells and goblet cells. Only a few areas of normal cultivated corneal epithelial cells were found. Conclusions: We suggest that the process of allograft rejection is responsible for the corneal epithelial loss and that this is followed by conjunctival invasion onto the amniotic membrane.