ABSTRACT.Purpose: To evaluate the results of penetrating corneal transplantation at a university hospital in Brazil. Methods: A prospective cohort study was conducted on 146 patients who underwent penetrating keratoplasty at the University Hospital, Faculty of Medicine of Ribeira˜o Preto, University of Sa˜o Paulo, Brazil. The participants were followed postoperatively for 36 months or until graft failure. Results: In this period, 49% of the grafts lost transparency. All the corneal diseases analysed were present in about the same proportions, except for keratoconus and bullous keratopathy, which showed 3% and 73% rates of graft oedema, respectively. Only 8% of the failures could be attributed to rejection. Other variables such as age, multiple surgeries and previous eye conditions could not explain the high rate of graft failure. Non-adherence to postoperative care increased with age, with a significant association between this behaviour and the rate of graft failure in the older age group. Keratoconus seems to be much less demanding and bullous keratopathy seems to be more exigent in terms of corneal transplantation than other corneal diseases. Conclusion: Although it involves an apparently simple surgical procedure, corneal transplantation is a demanding enterprise that can lead to very poor results under unfavourable conditions.