PURPOSE: To investigate the incidence, causative organisms, and visual acuity outcomes associated with endophthalmitis after pars plana vitrectomy. DESIGN: Retrospective, noncomparative, consecutive case series. METHODS: The medical records were reviewed of all patients who developed acute onset postoperative endophthalmitis (within 6 weeks of surgery) after pars plana vitrectomy at Bascom Palmer Eye Institute be tween January 1, 1984 and December 31, 2003. RESULTS: During the 20-year study interval, the overall incidence rate of postvitrectomy endophthalmitis was 0.039% (6/15,326). Cultured organisms were Staphylococcus aureus (n = 3), Proteus mirabilus (n = 1), and Staphylococcus epidermidis/Pseudomonas aeruginosa (n = 1); one case was culture,negative. Visual acuity after treatment for endophthalmitis ranged from 2/200 to no light perception, with a final vision of light perception or no light perception in four of six (67%) eyes. CONCLUSION: The incidence of endophthalmitis after pars plana vitrectomy is low but the visual acuity outcomes after treatment are generally poor. (C) 2004 by Elsevier Inc. All rights reserved.