To report a case of corneal ulcer due to Alcaligenes faecalis in a patient with a preexisting corneal ulcer.

A 58-year-old male patient presented with a corneal ulcer without a history of any trauma. The patient had a history of corneal ulcer 9 months earlier. The patient had previously been diagnosed with diabetic retinopathy and neovascular glaucoma, and his visual acuity was no light perception. Corneal scraping and culture yielded Alcaligenes faecalis susceptible to most antibiotics in the antibiotic susceptibility test. After treatment with empirical systemic antibiotics and eyedrops, his eye improved with a remaining corneal scar.

Alcaligenes faecalis should be considered as a causal pathogen of corneal ulcer in patients with suspicious compromised ocular surface, such as previous corneal ulcer.