In Japan, we experienced the first case of Hafnia alvei septicemia with shock and disseminated intravascular coagulation (DIC) in an adult with postoperative lung cancer. A 63 year-old male, who had been followed up in our department since 1987, was admitted to our hospital with the complaints of fever, hemoptysis and dyspnea on June 25, 1989. After admission, he was treated with sulbactam/cefoperazone 4 g/day intravenously for suspicion of respiratory-tract infection. After antibiotic administration, the fever subsided and the general condition became almost good. The patient experienced fever again after the antibiotic was stopped. For this reason subsequent Clavulanic acid/Amoxicillin, Flomoxef, and Ceftazidime was administered, but was not effective. Therefore septicemia was suspected and blood culture was done. The bacteria isolated from blood culture was identified as Hafnia alvei. Hafnia alvei is a gram-negative organism belonging to the Enterobacteriaceae family and quite rare pathogen in human.