To evaluate the long-term outcome of cultivated oral mucosal epithelial transplantation (COMET) in treatment of eyes with total limbal stem cell deficiency. Noncomparative, retrospective, interventional case series. Forty eyes in 36 patients with total limbal stem cell deficiency (Stevens-Johnson syndrome in 12 eyes, chemical or thermal burns in 11 eyes, ocular cicatricial pemphigoid OCP in 9 eyes, pseudo-OCP in 7 eyes, and gelatinous drop-like dystrophy in 1 eye) were treated at the Department of Ophthalmology, Tokyo Dental College, Chiba, Japan. Cultivated autologous oral mucosal epithelial sheets were transplanted onto the ocular surface in eyes with total limbal stem cell deficiency. Reconstruction of a stable ocular surface with a clear appearance and no epithelial defects, reduction in fibrovascular tissue invasion of corneal surface, a functional fornix, change in visual acuity, and postoperative complications. The mean follow-up period was 25.5 months (range, 6-54.9 months). Kaplan-Meier analysis of a corneal surface stability revealed an early decline in transplanted oral mucosal epithelial stability over the first 6 months, remaining comparatively stable thereafter (1 year, 64.8%; 2 years, 59.0%; and 3 years, 53.1%). Postoperative persistent epithelial failure developed within the first 3 months in 9 eyes. Early epithelial failure was associated closely with preoperative corneal defects. Gradual fibrovascular tissue invasion of the corneal surface was observed in 8 eyes and was marked in cases of OCP. Survival of a functional fornix decreased progressively until approximately 6 months. Postoperative visual acuity seemed to be related to the presence of corneal opacity. Complications included stromal melting or perforation in 8 eyes, infectious keratitis in 2 eyes, glaucoma in 8 eyes, and recurrence of herpetic keratitis in 1 eye. Corneal melting or perforation and infectious keratitis were associated closely with persistent epithelial defects after COMET. The transplantation of cultivated oral mucosal epithelial sheets offers a viable and safe alternative in the reconstruction of a stable ocular surface. Epithelialization of the corneal surface is very important not only in obtaining a satisfactory long-term outcome, but also in achieving a lower incidence of complications. The author(s) have no proprietary or commercial interest in any materials discussed in this article.