Objective To review the distribution and shifting trends of cultured bacteria from the aqueous humor and the vitreous body. Methods A retrospective analysis on distribution of Gram′s stain, the distribution and change of isolates was performed in 522 specimens (aqueous humor,261 and vitreous body,261) of patients with suspected endophthalmitis during a 10 year period (1989 1998). Results The positive cultures were 119 (aqueous humor,44 and vitreous body,75) of 522 specimens. The average positive rate was 22.8%. Gram positive cocci constituting 45.4%(54) of total isolates followed by Gram negative bacilli,34.5%(41);Gram positive bacilli, 20.2%(24). In the positive bacterial cultures, enterobacteriaceae was the most common isolate, 18.5%, and the next was micrococcus, 16.0%; coagulase negative staphylococcus,12.6%; and pseudomonas,10.9%.Comparing the data from 1989 through 1993 with the data from 1994 through 1998, the frequency of Gram positive cocci had no significant change, while the frequency of Gram positive bacilli was decreased and the percentage of Gram′s negative bacilli was increased. Conclusions Gram positive cocci and Gram negative bacilli are the predominant pathogens of bacterial endophthalmitis. The percentage of Gram′s negative bacilli has increased for 5 years. It is very important to comprehend the distribution and shifting trends of these pathogenic bacteria for diagnosis, prevention and treatment of bacterial endophthalmitis.