To our knowledge, Flavobacterium indologenes has never been reported as a cause of bacteremia in humans. F. indologenes bacteremia was diagnosed in 12 patients at a tertiary referral center in southern Taiwan between 1 January 1992 and 31 December 1994. Six of these patients had ventilator-associated pneumonia, two had primary bacteremia, and one patient each had pyonephrosis, peritonitis, biliary tract infection, and surgical wound infection. Five patients (42%) had malignancies, and three (25%) had multiple burns. Polymicrobial bacteremia was diagnosed in eight patients (67%). Two (17%) of the patients in this study died; both had polymicrobial bacteremia. Antimicrobial susceptibility testing of the blood isolates from the 12 patients showed that > 90% of the isolates were susceptible to piperacillin, cefoperazone, ceftazidime, and minocycline. The chromatograms of esterified fatty acids for the isolates were identical. F. indologenes should be considered an etiologic agent of bloodstream infection, especially in hospitalized patients with severe underlying diseases.