Purpose: To survey the changes in indications for penetrating keratoplasty (PKP) and reevaluate the risk factors for allograft rejection and graft failure. Methods: We evaluated the records of 396 eyes of 335 patients who had undergone PKP at the Tokyo University Hospital between 1987 and 1997. Clinical results were analyzed by the Kaplan-Meier life table method and the log-rank test. Results: The overall rates of graft survival and rejection-free graft survival at 10 years were 72.2% sind 76.8%, respectively. The rates of graft survival and rejection-free graft survival were 98.8% and 86.6% in keratoconus, 87.0% and 56.5% in herpetic keratitis, 76.9% and 73.1% in corneal dystrophy and degeneration, 69.4% and 80.6% in nonherpetic keratitis, 62.5% and 75.0% in chemical burns, 61.8% and 72.1% in regrafting, and 51.1% and 79.8% in bullous keratopathy, respectively. The graft survival rates were statistically higher in the PKP alone group than in the combined operation group. The graft survival and rejection-free graft survival rates were statistically higher in the first operation group than in the regrafted;roup, and in the avascular cornea group than in the vascular cornea group. Conclusions: We recognized changes in indications for PKP. Combined operation, reoperation, and vascularization of recipient cornea were risk factors for graft failure. Jpn J Ophthalmol 2000;44:139-145 (C) 2000 Japanese Ophthalmological Society.