PURPOSE: To evaluate the use of the Boston keratoprosthesis type I implantation in patients with mucous membrane pemphigoid (MMP). METHODS: Retrospective review of 8 eyes of 8 patients with severe ocular surface disease and corneal blindness as a result of MMP who underwent Boston keratoprosthesis type I implantation at the Massachusetts Eye and Ear Infirmary from January 1, 2000, through December 31, 2009. The main outcome measures were best-corrected visual acuity, keratoprosthesis retention, and postoperative complications. RESULTS: The mean age of patients was 71.3 years (range, 55-94 years), and the mean duration of their disease preoperatively was 6.1 years (range, 1.7-11.4 years). Visual acuity after the surgery improved to 20/200 or better in 6 eyes (75%) and to 20/40 or better in 3 eyes (37.5%). Only 1 of 6 eyes (16.7%) was able to maintain visual acuity of 20/200 or better over a mean follow-up period of 3.2 years. Five of the 8 Boston keratoprosthesis type I devices (62.5%) extruded or had to be replaced during a mean follow-up time of 1.7 ± 1.7 years. Loss of vision to worse than 20/200 during the follow-up period occurred because of keratoprosthesis type I extrusion, end-stage glaucoma, and retinal or choroidal detachment. CONCLUSIONS: The clinical outcomes of Boston keratoprosthesis type I implantation in MMP are guarded and, as judged from the literature, less favorable than those with the Boston keratoprosthesis type II for the same disease.