The author evaluated 142 patients aged 65 years or older with microbial keratitis. There were relatively high rates of Pseudomonas aeruginosa infection unassociated with contact lens wear and of Streptococcus pneumoniae infection. The rates of quasicommensal and enteric infections were not proportionately elevated. Corneal disease, use of topical corticosteroids and use of contact lenses were the main predisposing factors. Patients with diabetes mellitus, dementia or chronic alcoholism appeared to be at higher risk. Trauma was rarely a factor. Complications requiring surgery were common. Corneal perforation developed in 20% of the patients, and endophthalmitis developed in 6%. The elderly often do not tolerate intensive topical antibiotic treatment well. Supplementary subconjunctival antibiotic injections under local anesthesia may be necessary. Corneal tissue glue, tarsorrhaphy and conjunctival flaps are probably underused in this age group.