The progress in instrumentation and surgical techniques, as well as improvements in the knowledge of the biologic mechanisms have considerably enlarged the indications for keratoplasty. Even in unfavourable cases the prognosis has been notably improved by recent advances in medications and techniques to improve the conditions of the recipient and the operative technique, and also to limit the immunologic response. The use of impeccable instruments, meticulous selection of the graft and a refined surgical technique during the the operation are essential since neglect of any small detail may lead to failure of the operation. The graft and the recipient bed must be in perfect apposition. A very neat, smooth incision of the graft and the host window are imperative, as well as the application of a sufficient number of sutures. The sutures must be left in place for a sufficiently long period of time to ensure good cicatrization of the graft. Peripheral iridotomies or iridectomies facilitate the circulation of the aqueous humor avoiding the danger of postoperative pupillary block with all its consequences. The anterior chamber must be carefully restored, preferibly by air injection, to maintain the iris well away from the incision. It should be taken into account during the whole procedure that the endothelium is the most delicate and the most important structure of the graft as well as the host cornea. Contact with the instruments should be avoided and the sutures should provide good apposition of the endothelial edges. Early diagnosis and prompt adequate treatment of any accident or complication are essential. Undetected complications or incorrect management of the same may be responsible for failure of the operation and the final result may vary between a more or less opacified graft and the full-blown picture of phthisis bulbi. A number of illustrative cases are presented.