Purpose: The purpose of this report is to present an extremely rare case of endogenous Listeria monocytogenes endophthalmitis.Methods: A 72-year-old woman was diagnosed with endogenous endophthalmitis. Listeria monocytogenes was identified by culture of aqueous humor. Multiple investigations could not reveal any source of infection. An overview of other published cases is presented and a standardized treatment protocol is suggested.Results: Treatment consisted of topical therapy with antibiotics, corticosteroids, cycloplegics, and intraocular pressure-lowering agents, four intravitreal injections of vancomycin, an anterior chamber washout, intravenous amoxicillin, and eventually a pars plana vitrectomy. The inflammation subsided and the patient was discharged with a best-corrected visual acuity of 20/40.Conclusion: Our study emphasizes the importance of adequate microbiological testing and initiating appropriate treatment early in the management of endogenous endophthalmitis.