OBJECTIVE To investigate the clinical settings, management strategies, antibiotic sensitivities, and visual acuity outcomes for eyes with endophthalmitis caused by Haemophilus influenzae. METHODS Retrospective, noncomparative, consecutive case series. METHODS The medical records were reviewed of all patients treated for culture-proven H. influenzae endophthalmitis at a single institution between January 1, 1980, and December 31, 2002. METHODS Visual acuity and antibiotic sensitivities. RESULTS The study included 16 eyes of 16 patients with a median age of 68 years (range, 6 months-83 years) and a median follow-up of 26 months (range, 2 months-15 years). Clinical settings included post-trabeculectomy (n = 7), post-cataract surgery (n = 6), post-pars plana vitrectomy (n = 1), post-secondary intraocular lens insertion (n = 1), and post-suture removal from an extracapsular cataract wound (n = 1). Eleven (69%) cases were of delayed onset (>6 weeks from surgery/event), with a median interval between surgery/event and presentation with endophthalmitis of 18 months (range, 44 days-21 years); 5 (31%) cases were of acute onset (median, 6 days; range, 2-14 days). Presenting visual acuity was hand movements or better in 7 (44%) eyes. A vitreous tap and inject was performed initially in 9 (56%) eyes, and a vitrectomy was performed initially in the remaining 7 (44%) eyes. All eyes received intravitreal antibiotics on the day of presentation, and 11 (69%) received intravitreal dexamethasone. In vitro testing of the H. influenzae isolates revealed that 14 of 16 (88%) were sensitive to vancomycin, ampicillin, and trimethoprim/sulfamethoxazole; 15 of 16 (94%) were sensitive to aminoglycosides (1 isolate was resistant to gentamicin); and all were sensitive to cephalosporins, fluoroquinolones, and carbapenems. The organisms were sensitive to at least 1 of the initial antibiotics administered in all cases. Final visual acuity was 5/200 or better in 6 (38%) eyes, and 6 (38%) eyes had a final visual acuity of no light perception. CONCLUSIONS Endophthalmitis caused by H. influenzae is generally associated with poor visual outcomes despite prompt treatment with intravitreal antibiotics to which the organisms were sensitive.