Background: The rapid antibiotics treatment targeted to a specific pathogen can improve clinical out- comes of septicemia. We aimed to evaluate the clinical characteristics and outcomes of biliary septicemia caused by cholangitis or cholecystitis according to causative organisms.Methods: We performed a retrospective cohort study in 151 patients diagnosed with cholangitis or chole- cystitis with bacterial septicemia from January 2013 to December 2015. All patients showed clinical evi- dence of biliary tract infection and had blood isolates that demonstrated septicemia. Results: Gram-negative, gram-positive, and both types of bacteria caused 84.1％ (127/151), 13.2％ (20/151), and 2.6％ (4/151) episodes of septicemia, respectively. The most common infecting organisms were Es- cherichia coli among gram-negative bacteria and Enterococcus species ( Enterococcus casseliflavus and En- terococcus faecalis ) among gram-positive bacteria. There were no differences in mortality, re-admission rate, and need for emergency decompression procedures between the gram-positive and gram-negative septicemia groups. In univariate analysis, previous gastrectomy history was associated with gram-positive bacteremia. Multivariate analysis also showed that previous gastrectomy history was strongly associated with gram-positive septicemia (Odds ratio = 5.47, 95％ CI: 1.19–25.23; P = 0.029). Conclusions: Previous gastrectomy history was related to biliary septicemia induced by gram-positive organisms. This information would aid the choice of empirical antibiotics.