A corneal ulcer caused by Clostridium perfringens developed in a 76-year-old woman with Sjögren's syndrome. Experimental C perfringens keratitis was induced in rabbits by the intrastromal injection of 10(7) organisms. In both our patient and the experimental animals, a bullous lesion overlay the affected area of the cornea. This may be a specific lesion in clostridial infections of the cornea. Clostridium perfringens should be regarded as an opportunistic corneal pathogen, and anaerobic cultures should be performed in all cases of suspected bacterial corneal ulcer.