Over a 14-year period from 1974 to 1988, 12 eyes of 11 patients with pellucid marginal corneal degeneration underwent penetrating keratoplasty. Peripheral corneal thinning required a large eccentric graft in each case. Follow-up ranged from one to eight years (mean, three years). One graft failed because of a persistent epithelial defect with keratolysis of the wound. Although endothelial allograft rejection was common, occurring in seven of 11 (64%) clear grafts, no graft failed because of rejection. Other complications included retinal detachment and a bacterial corneal ulcer. Suture erosion and vascularization of the graft were not problems. Postoperative spectacle correction was dispensed an average of 11 months after surgery. Visual acuity in seven patients without amblyopia, retinal disease, or a previous corneal ulcer at the time of spectacle correction ranged from 20/20 to 20/40 (mean, 20/30). Average final keratometric astigmatism in these patients was 2.46 diopters (range, 0.00 to 5.25 diopters). We believe that penetrating keratoplasty offers an excellent surgical result for patients with pellucid marginal corneal degeneration.