An adult with cutaneous diphtheria was admitted with bilateral purulent conjunctivitis and a perforated eye with most of the cornea absent due to Corynebacterium diphtheriae. At the time of admission of grayish patch of corneal epithelium was noted in the other eye, and in the next 24 hours there developed a large corneal perforation with dissolution of much of the cornea. Involvement of the external eye in diphtheria is rare but it is usually associated with cutaneous forms of the disease. Cutaneous diphtheria has been prominent in several recent outbreaks in the United States. Prompt recognition, early antibiotic treatment, and neutralization of the toxin with antitoxin are required for successful therapy.