From 1982 to 1994, 45 patients (1.22 episodes per 10,000 discharged patients) were treated for citrobacter bacteremia at National Taiwan University Hospital (Taipei). All patients had at least one underlying disease. Citrobacter bacteremia most commonly occurred in patients with malignancies (48.9%) or hepatobiliary stones (22.2%). Intraabdominal tumors comprised the majority (59.1%) of malignancies. Bacteremia commonly originated from sites such as the abdominal cavity (51.1%), urinary tract (20%), and lung (11.1%). Polymicrobial bacteremia was diagnosed in 15 patients (33.3%); for nine (60%) of these patients, the source of the infection was intraabdominal. Prior treatment with a third-generation cephalosporin was significantly associated (P < .01) with the development of multidrug resistance among the isolates. The mortality associated with citrobacter bacteremia was 17.8%. Poor prognostic factors included pneumonia, altered mental status on presentation, hypothermia, oliguria, septic shock, deterioration in mental status, hyperbilirubinemia, azotemia, and thrombocytopenia. Combination therapy, as compared with other regimens, improved the outcome of citrobacter bacteremia.