Purpose: To investigate the anatomical and functional outcomes of acute-onset endophthalmitis after small-gauge vitrectomy. Methods: Retrospective case series of patients who underwent 23- or 25-gauge vitrectomy at four centres in Sweden between 2008 and 2012. Postvitrectomy endophthalmitis was identified through the search of the journal records of each institution, and the diagnosis was based on clinical criteria regardless of culture results. Results: Twenty-four patients (24 eyes) were included. The incidence of endophthalmitis following small-gauge vitrectomy was 0.14%. Indications for small-gauge vitrectomy enclosed epiretinal membrane (n=13), retinal detachment (n=5) and others (n=6). Surgical technique included 23- and 25-gauge vitrectomy (23:1). Four eyes had sutured sclerotomies, and two had postoperative hypotony <7mmHg. Days to endophthalmitis presentation varied between 1 and 21 (mean 66). Treatment methods included the following: tap and antibiotic injection (n=7), tap, antibiotic injection with subsequent vitrectomy (n=2) and prompt vitrectomy with antibiotics (n=15). Sixteen eyes (66.7%) were culture positive, whereas the other eight cases were culture negative. Anatomical results included evisceration (n=1), phthisis (n=1), and globe intact (n=22). Presenting best corrected visual acuity (BCVA) were hand motion (n=14), light perception (n=7), counting fingers (n=2), and no data (n=1). Functionally 19 eyes (79%) had Snellen VA 0.1; 11 eyes (46%) had VA 0.5 Mean logMar BCVA preoperatively and at the last follow-up were 2.07 +/- 0.6 and 0.79 +/- 0.99, respectively. Conclusions: In spite of good anatomical and functional results, this study showed higher rate of endophthalmitis than the latest reports suggesting that small-gauge vitrectomy has reached the safety level of standard 20-gauge vitrectomy when infectious endophthalmitis is concerned.