Raoultella ornithinolytica is a rare pathogen in human infection and bacteremic cases had been scarcely reported. For further comprehension of the rare infection, we summarized clinical characteristics of 6 cases that were detected at our medical facility and 5 cases from previous literature. The most common infectious focus was biliary infection and elderly patients with a history of any biliary intervention or malignancy were considered to be at a great risk for the infection. The prognosis of the patients was quite satisfactory. Bacterial identification in this report was performed on the basis of biochemical tests alone, and further investigations by molecular analysis are required to confirm our findings. (C) 2014, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.