Background Endophthalmitis is a serious,sight-threatening condition.Identifying the causative microorganisms is very important for available treatment of endophthalmitis.Objective This survey was to analyze the spectrum of organisms causing culture-proven endophthalmitis and their sensitivities to commonly antimicrobial agents.Methods Medical data of patients with culture-proven endophthalmitis at Zhongshan Ophthalmic Center from January 2003 through December 2010 were respectively reviewed.The outcomes included intravitreal isolates and antibiotic sensitivities were analyzed.Results Four hundred and sixty-nine strains of organisms were isolated from 447 eyes of 447 patients with infective endophthalmitis,including 22 eyes of polymicrobial infection.In the organisms,gram-positive organisms were 241 (51.4％),fungi were 125 (26.7％) and gram-negative organisms were 103 (22.0％).The most common organisms were Staphylococcus epidermidis in 29.4％,Aspergillus in 7.7％ and Pseudomonas aeruginosa in 5.3％.In this group of infective patients,the most common clinic settings were posttraumatic endophthalmitis (72.7％),and then were postoperative endophthalmitis (10.5％),endogenous endophthalmitis (9.8％) and keratitis (6.9％).Most gram-positive organism and gram-negative organism were sensitive to levofloxacin and cefoperazone.The susceptibility rate of gram-positive organism to chloromycetin was increased in 2007-2010 years compared with 2003-2006 years (x2=5.398,P＜0.05).The susceptibility rate to ciprofloxacin of gram-negative organisms declined (x2 =5.398,P ＜ 0.05),but that to rifampicin increased in the duration of 2007-2010 compared with 2003-2006 (x2 =4.500,P ＜ 0.05).Conclusions Gram-positive organisms are the most commonly causative organisms of endophthalmitis.Most bacterial organisms are sensitive to levofloxacin and cefoperazone.Local data of culturing and susceptibility test offers a guideline for the treatment of infectious endophthalmitis.