Phlyctenules and catarrhal infiltrates of the human cornea have been described in association with staphylococcal blepharitis. Rabbits immunized and boosted with phenol-inactivated Staphylococcus aureus had a fourfold or greater increase in antibody titer to S aureus and delayed hypersensitivity to S aureus. After topical challenge with viable S aureus, the rabbits in this model had vascularized, elevated, nodular infiltrates of the cornea resembling phylctenules in humans and peripheral corneal infiltrates running parallel to the limbus and separated from it by a lucid interval resembling catarrhal infiltrates in humans. The nodular corneal infiltrates were found in a subepithelial location and were composed of vessels, polymorphonuclear leukocytes and mononuclear cells, including lymphocytes, plasma cells, and macrophages. The peripheral corneal infiltrates separated from the limbus by a lucid interval were found in the anterior stroma beneath the corneal epithelium and were composed of polymorphonuclear leukocytes and mononuclear cells.