As an architectonic, transparent and dioptric structure, the cornea plays an important role in the anatomy and physiology of the eye. Corneal grafting consists of replacing an irreversibly damaged cornea by a healthy cornea taken from a donor. Lamellar and transfixiant keratoplasty techniques are now well codified in their modus operandi and their indications. The marvellous and dramatic results achieved in some types of corneal lesions, such as keratoconus, stand in sharp contrast with the still mediocre results obtained in other lesions. Technical, surgical and above all biological research is therefore needed to improve our knowledge of rejection mechanisms and surgical failures.