Yersinia pseudotuberculosis is a relatively infrequent cause of human infections, mostly as intestinal yersinosis. A septicemic form of Y. pseudotuberculosis infection has been reported only rarely. It is usually seen in patients with underlying disorders such as diabetes, hepatic cirrhosis or iron overload. A 63-year-old man with diabetes mellitus and liver fibrosis was admitted to Asan Medical Center via emergency department because of epigastric pain, fever and watery diarrhea; he was septic. The stool culture did not grow Salmonella, Shigella, or Yersinia. But, in the blood culture Y. pseudotuberculosis grew from one anaerobic vial among two sets of aerobic and anaerobic blood cultures. Serotype of Y. pseudotuberculosis strain was could not be determined because it was a rough type. The isolate was positive in the autoagglutination test and polymerase chain reaction for the virF gene. The serum levels of iron, TIBC and ferritin were within normal range. The patient received ceftriaxone therapy for 3 days and was discharged with a clinical improvement. (Korean J Clin Microbiol 2001;4:68-71)