A retrospective clinicomicrobiological study of 228 patients with bacterial corneal ulcers was performed. Positive cultures of corneal ulcer samples were obtained from 68% of all patients. A high incidence of Staphylococcus epidermidis was isolated from patients' ulcers, Staphylococcus aureus, Pseudomonas, Streptococcus pneumoniae, and Streptococcus were the next most frequent pathogens. Of some help in identifying the causative organism were the locations of the ulcer, the presence or absence of hypopyon and the frequency of perforation of the ulcer. Cephaloridine, gentamicin and polymyxin were found to be the most effective therapy. Gram strains of ulcer samples were positive for organisms in only 13% of patients and accordingly were not considered useful in determining initial therapy of ulcers. Since corneal and conjunctival cultures in the majority of the control group were negative, one can presume that most of the S. epidermidis isolated from patients' ulcers was exogenous in nature.